Of course you can't kill yourself. Yes, I had that thought too many times the first 3 years of having this nightmare called tmj. The pain is unbelievable and few people understand or even care that the pain is so bad. 25 years ago when I woke up one morning with excruciating pain, tmj was considered a "new" and highly misunderstood dysfunction.
Sadly that even though tmj is not new anymore, too many doctors and dentists have no idea what to do. You go to a doctor with earaches or sore throats or headaches and not one doctor will even think you might have tmj, but yet they'll say nothing is wrong with you and even tell you that it's all in your head (no pun intended) if you complain too much about different pains in the head and to see therapy.
Don't let tmj defeat you. There is a lot that can be done and the fact that there is the internet with good information and a few very good support groups is wonderful. If you have just been diagnosed with tmj there is a good possibility that you will be "cured" or at least manageable.
Do you know what caused or started your tmj? Was it the braces? Do you still have the braces on? If the answer is yes to these questions, be patient. Your jaw is going through changes and trying to find its correct balanced bite. Do not remove the braces until your bite is balanced and pain-free. This might sound overly critical, but if your current orthodontist doesn't seem to know how to balance your bite adjusting the braces, etc., go to a different one.
A bite splint can possibly be a big help for you now whether you have braces on or not. All your other questions and points are also tmj symptoms - earaches or fullness; pain anywhere possible in the head, neck and shoulders (and even back); swollen sinuses can aggravate tmj and vice versus. I used to frequently take sudafed or actifed to help my tmj.
And as for your last paragraph, tmj zaps me of energy which has made me feel that my health has never been "good" my whole life. It can be very depressing and when I finally started taking anti-depressants, it helped my tmj pain and general health at least for a few years. Now, i'm just getting older and my body isn't liking it.
There are things you can do now to help yourself - use lots of moist heat, and even ice helps. I use both frequently. Go on a soft food diet for the next several weeks or months, do not chew gum or ice, don't open your mouth too wide, be gentle to the jaws, and sleep on a good cervical pillow. Ask your ortho, dentist or doctor for a script of valium for a few weeks to relax your jaw while sleeping. Ibuprofen seems to be the better pain reliever if you can take it (take with food though), go to a massage therapist regularly who is trained in tmj or ask your doctor for a referral to a physical therapist (again, make sure they are trained in tmj). Watch your posture especially in front of the computer, do lots of research on the internet and there are a few excellent books on tmj with good information, and check out the website nismat.Org/ptcor/tmj/ for just some good general information.
That's a lot of information to give you for not being sure what your circumstances are. I hope you can filter out what you can use to help you, but one thing again - I personally do recommend bite splints for sleeping.
Take care of yourself and remember, suicide is not even an option. Life has so much going on and there's so much we can do if we want that you don't want to miss anything. And aren't you curious what might happen tomorrow or next year? You just want the pain to go away. So do it. But be pro-active to help yourself control that pain. Do anything and everything that you can possibly do to help yourself. One thing I didn't mention before is to check out a pain doctor or clini or even neurologist if your ortho, dentist or family doctor can't help you control the pain. Don't give up!!!! Fight!
God bless...
Carol