I suggest you start to track this on a calendar to figure out if this is just normal and related to the phase of your menstrual cycle you are in, for example, the discharge may be during ovulation, or just before menstruation.
Staying dry and cool are important. Some general guidelines:
Wear cotton panties to wick away moisture
Make sure it is full crotch panties, not strings
Sleep without your panties if it is safe to do so
Do not use softeners or drying sheets with your panties. Make sure you rinse them out very well to remove soap residue.
Wash with only clean water and your fingers.
Use panty liners during the day to absorb heavy discharge and keep you dry
Do not douche or wash inside your vagina
Pat yourself dry whenever you are wet. Get out of wet clothes as soon as possible
Take special care about shaving products used
Do not wear tight pants or nylons
Wipe from the front to the back
Make sure your hands and toys are clean when you masturbate
Follow a health diet. Cut down on sugars and add some natural yogurt (with live cultures)
If you are at risk for diabetes, monitor it very closely
Avoid ejaculation without condoms if possible
Make sure you change tampons regularly and that you do not have an allergic reaction to the pads you are using
When you burn after urination, use a small spray bottle with water to clean and pat yourself dry. Drink enough water to dilute your urine and visit the toilet immediately when you feel the need.
Use a mirror and inspect yourself for redness or scratches/sores and strange discharge every once in a while (with your monthly breast self exam is a good idea)
Monitor yourself for smells and signs of yeast/bacterial infections, as well as an UTI.
These guidelines are very broad, but even your doctor could not find anything....