I can't do this anymore...

I moved cross country and am still trying to do online classes through the college I was attending. I am awful at online classes. I don't know why, but they're really challenging for me. I only had two for the first part of the semester but I got dropped from one and I'm thinking about dropping the rest of my classes because I don't want to fail. I feel overwhelmed and scared and stressed and angry and upset. My stomach has been in knots and I've felt nauseous and like I'm about to throw up for most of this week. I feel like I'm useless and a burden to my husband because I haven't been able to find a job so I can only contribute a little bit to bills and things. I just can't do this anymore....