am i in the early stages of schizophrenia

My name is Matt and I'm a 22 year old male. About 9 months ago I started having panic attacks and all the classic symptoms of anxiety. I never questioned my sanity even on my worst days. I accepted the fact that I had anxiety and things started getting significantly better . However, about a month agi, after about a week straight of nothing but stress, I started feeling weird. I felt like someone locked me in my own mind and threw away the key. I'm not seeing things, I'm not hearing things, and I'm still in touch with reality. Due to the feeling I experienced, I started in on the "I'm losing my mind" kick. My thoughts pass through my head faster than a funny car on a drag strip. I'm now getting songs and phrases stuck in my head. I've had this my whole life, but now its different. The songs and phrases sometimes start running together, and when I try to summon a thought, the only things that come up are these songs and phrases. I'm scared because I can't focus on anything, and reality feels so far away. It feels like everything I do is such a blur. I go out and laugh and carry on with my friends but it doesn't feel like me doing it. I feel so detached from myself I don't even understand how I can even talk. Another thing is my speech, sometimes ill lose what I'm saying mid sentence out of pure confusion, and I'm always mixing up and stumbling over my own words. I went to the er about a week ago and checked myself into the mental health unit. The doctors said that I suffered from a manic episode. My problem with that is the only symptoms of mania I had were the racing thoughts. They released me the next day and said that they had no good reason to keep me there. I was diagnosed with manic depression. I'm just worried because I don't think I'm bipolar because I don't have problem with my moods, just my thoughts. I've got so many good things in my life and I don't want to lose it. I'm so scared of developing schizophrenia, but if I am, I want to catch it early before it fully develops .