There are no lab tests for bipolar disorder, however finding questionares you can answer are easy to find. I found and studied several reputable ones before creating my own. When researching, I look for sights that end in .org and .gov. Their information seems more reliable to me.
I am bipolar. I was originally diagnosed with depression. This is really common because bipolar people usually don't complain about their mania. The antidepressants worsened my mania symptoms. I knew in my heart that something was wrong, as it seems you do.
So, take some mental health quizzes at some reputable sights and make notes to take to a doctor if you feel you need one.
Good luck to you. YOU ARE NOT ALONE! I know a LOT of people like me. If you have any questions or need someone to talk to, let me know. It helps me to help others.