Hi there. I'm sorry you are having such a hard time.
I know the feeling, I'm having the same problem with just one class and feeling quite similar about it. Luckily for me, I won't have to worry about the subject again after the exam Monday (assuming I pass!).
How far into the class are you and is it compulsory? If there is an option of swapping out, that might be a good idea. Otherwise, like Bevlynn said, all you can really do is push through it. Do a bit of work and reward yourself. When you aren't studying, I know its harder than it sounds, but try not to think about it. Distract yourself by hanging around with friends, watching, reading or playing something, taking a walk, whatever makes you happy and relaxed. And think about what the worse thing that could happen is. If its similar to my course, the worse that could happen is repeating the course next time. Unlikely and worst case scenario. Not a fun thing, but all it means is an extra semester to your time studying. In the grand scheme of things, it doesn't make a huge difference.
The other thing is, can you talk to your professor about it, ask her to go through it in a different way? Or do you have a tutor or such that might be more helpful? If not, can you afford to consider private tuition? Even organising study sessions with classmates can help!
If nothing else, you have a lot of people on these forums who would like to serve as someone supportive to talk to.
I'd be happy to chat more about you with it or just listen if you'd ever like to send me a
PM. Any way I can help.