Print out the screening tool from Mayo Clinic (http://www.mayoclinic.com/health/bipolar-disorder/DS00356) and take it to your doctor or another mental health professional. If money is an issue, you can contact your county's department of human services and ask for mental health. If you do have bipolar, or show enough symptoms, you can get a referral to a counselor. That's the best person to talk to.
I would talk to your family doctor and then they can make a referral to a psychiatrist who would be the one to give you a diagnosis.
Reaching out for help is important. I don't know your family dynamics so I can't tell you if it is safe to tell your parent's. I kept the diagnosis from my family for over a year. Didn't tell them I was off work, nothing. And I was 32 at the time. When I finally told them it was a relief and the only thing they were perturbed about is that I didn't tell them sooner. My family has all been great about it. If your family isn't a support maybe try a friend. Friends are more fickle because they don't have that family bond keeping them engaged, but it is better than trying to keep this all inside yourself.
Start by talking to your doctor. They can help you decide the next step. You may need to see a psychiatrist to get a diagnoses. My husband's psych sent him to a specialist in bipolar to get the dx. It made all the difference in our lives.
Why do you think you are bipolar??