learning

I want to pursue a career, but im not confident in my writing skills to enter college. I took a placement test and it stated that i was prepared to enter college level courses, but i think otherwise. I don't think i know how to use vivid description, and when i do write i don't have much to say on the topic. When i was enrolled in courses i passed everything up until it came time to write essay. I didn't know how to start. How to put other people's words into my own words, Or how to organize the paper. I didn't want to make an embarrasement of myself so i just stopped going althogether and wound up with straight f's.  I get disorganized in my writing and find it difficulty to put my thoughts onto paper. I still don't understand what it means for a comma to go between an indepent clause and main clause. People tell me to place them when i rest in my speech. But that does not seem to help me.I feel like i write at an eight grade level. I get depressed because i feel like im never going to learn, and i want nothing more than be able to explain myself on paper. Im writing this because maybe someone out there has some advice for me. I don't want to give up and these depression pills aren't working. I need to do something to improve. I am just recently getting into the habit of reading, so that could help. Does anyone out there have some advice for me??