First of all, you are taking a great big awesome step by posting here. That in itself raises awareness. As for your doctor, I would personally get a lawyer or get free consultation from one. Explain your situation as you have explained it here. Ask what the laws are for warning against taking expired medication (which even I know is HIGHLY unadvisable). And then, if your consultation proves that you may have a case, sue your Doc. In my opinion, what she did was complete negligence. Why have you take an expired medication when she has a prescription pad right in front of her?
Here is info on Trazodone, excerpted from WebMD:
Trazodone Oral Interactions
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

This drug should not be used with the following medications because very serious interactions may occur: sibutramine, triazolam.

If you are currently using any of the medications listed above, tell your doctor or pharmacist before starting trazodone.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: other antidepressants (e.g., amitriptyline, bupropion, fluoxetine, nefazodone, venlafaxine), digoxin, drugs affecting liver enzymes that remove trazodone from your body (such as azole antifungals including ketoconazole/itraconazole, HIV protease inhibitor drugs including atazanavir/indinavir/ritonavir, macrolide antibiotics including erythromycin, cimetidine, rifamycins including rifampin, St. John's wort, certain anti-seizure medications including carbamazepine), other drugs that can cause bleeding/bruising (e.g., anticoagulants such as heparin or warfarin, antiplatelet drugs including NSAIDs such as ibuprofen), drugs for high blood pressure, ginkgo, MAO inhibitors (e.g., furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine).

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., phenytoin), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., chlorpromazine, risperidone).

Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain ingredients that may cause drowsiness. Ask your pharmacist about using those products safely.

Check all prescription and nonprescription medicine labels carefully since many medications contain pain relievers/fever reducers (NSAIDs such as aspirin, ibuprofen, naproxen) that may increase your risk for bleeding if taken together with this drug. Low-dose aspirin should be continued if prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually at dosages of 81-325 milligrams per day). Consult your doctor or pharmacist for more details.

Before you have surgery with a general anesthetic, including dental surgery, tell the doctor or dentist you are taking trazodone.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

Trazodone Oral Side Effects
See also the Warning section.

Nausea, vomiting, diarrhea, drowsiness, dizziness, tiredness, blurred vision, changes in weight, headache, muscle ache/pain, dry mouth, bad taste in the mouth, stuffy nose, constipation, or change in sexual interest/ability may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: fainting, shaking (tremors), nightmares, ringing in the ears, problems urinating, blood in urine.

Tell your doctor immediately if any of these rare but very serious side effects occur: slow/fast/irregular heartbeat, signs of infection (e.g., fever, persistent sore throat), seizures, shortness of breath, stomach/abdominal pain, black stools, vomit that looks like coffee grounds, easy bruising/bleeding.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest/jaw/left arm pain.

For males, in the very unlikely event you have a painful or prolonged erection (priapism) lasting 4 or more hours, stop using this drug and seek immediate medical attention, or permanent problems could occur.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

AND MOST IMPORTANT OF ALL: Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.