Hi there, welcome to the forum(s)
I am Bipolar-II(mild) and would suggest for you to be certain is to take it up with a mental health professional, self-analyzing, and just perhaps, reading about it, will not get you the right diagnose, if there really is a problem.
Today so many people are tempted to self analyze and self diagnose, which can create more stress for a person.
Also there are so many disorders, and symptoms can be similar but do not mean a person has one in particular, even the DSM-IV can be slightly off at times, I myslef would first go for a physical and then be sure to rule out anything like hormonal imbalances, thyroid disorder, diabetes, Lyme's disease, etc. Then if things are fine, seek a mental health professional, maybe even starting with a psychologist first, who may refer you to a psychiatrist if necessary.
Though hard, try not to get too upset, and if things turn out that you are Bipolar or have an other disorder(s) there are medications with talk therapy that can help put you on track.
Fell free to come here and post anytime, and even try to log on to "chat", there are lot of terrific members here to talk with

DE

In giving advice seek to help, not please your friend
SOLON