I feel like a failure..?

I'm 17, girl, soon to be a senior. Ever since my father lost his career in 2005, my grades plummeted. I was very depressed, and was not medicated for a long time. Middle school was, was very traumatic for me. And 9th grade's gpa was only a 2.5, last year was 2.6 and this year is around 3.1ish..I never took a foreign language because my short term memory is very poor. I was also in low math classes. I tried taking chemistry at a lower level but it was too hard to comprehend for me. I have a slightly above average IQ but my computing is a bit slow I think. my mom thinks I'm a loser and has drilled in my head that I would never be able to get into or stay in a 4 year college without screwing up. I want to be a Highschool English teacher, so my mom said a 2 year would be better for me..But some how, I think I can do a 4 year..I just feel like such a moron. But those hard years took a really bad toll on my mentality then. I would like to look in the mirror and smile at my smart self but I just want to crumble to the ground in humiliation. Please help, I have no one to talk to.