Bipolar & using prozac for first time ... have you found antidepressants helpful

Hello. I take an anti depressant called sertraline. I find it helps me better than others. I also take thyroid medication. I should have a blood test every 6 months to make sure my levels are right, but because of my mental health I have been known to leave my blood tests for years. The doctors never chase me up which I wish they would because I'm sure that my thyroid makes me feel worse.

I have always had very low times and very high times. Sometimes I can change in mood a few times a day. I have always thought that I was "normal" until I've been seeing a councillor who believes I might have bipolar. Can you please tell me how I would know if I have bipolar?? When I feel high I feel like I can do anything and there are no limits to life. When I feel low, I want to die in my sleep. There's nothing particularly difficult or horrible in my life at the moment so it's hard for me to understand why I feel these things. My kids and partner don't know whether they are coming or going with me....I'm different from one minute to the next...

here is a good link to compare symptoms http://bipolar.about.com/cs/faqs/f/faq_bp2.htm  would you consider keeping a mood diary for a while it might be helpful in spotting patterns