Prescribed Celexa, doctor didn't tell me what he suspected, what happens next?

So I had my appointment today with my physician and he prescribed me Celexa.He didn't tell me what exactly he suspects. After almost 8 years of symptoms , which I never truly realized until recently what was going on, I finally went for help. Both of my sisters are bipolar, my uncle was as well and depression is common in my family also. It was hard to talk about it but I am sick of living with these severe mood swings. Feeling happy then in a split second depressed to my core for no reason at all. It usually rotates between happy (least often), anger, and depression (most often), but in a split second for no reason at all. These 'swings' can last anywhere from a few minutes, hours, days, weeks or even months and are unpredictable. Suicidal thoughts, my mind constantly racing non stop, memory getting worse, can't concentrate, relationships in turmoil, and my quality of life dwindling. I just want my life back, I've coped with it so far but it is getting worse and I can't take it anymore. I have a appointment in a month to see how effective it is, but I am wondering what will happen after that? Will I get referred to a psychiatrist for diagnosis? What tests will be done? I just want my life back! :(