I think I might need help

I dont know, lately I feel like I'm losing myself.
I'm so worried about school, exams and university, it just makes me feel ill.
Last week I broke down crying hard at school because the pressure got too much for me :S
I'm tired all the time. Today, i found that i lost 14 pounds (1 st. english weight measurement) and i'm officially underweight :S. I'm starting to become obsessed about what I eat and how many calories I ingest each day, its kind of scary.
I've also started to dwell on buzz and what happened between us and why it went so badly.
Sometimes I feel like its my fault.
My self esteem is going, I don't feel like I'm good enough anymore.
I'm really scared of failing. I don't want to stay in this same place for another year, it just brings back bad memories of buzz and I'm so tired of being isolated.
I think I might need to start seeing a therapist :S