School/grade stress only lasts a few months at the most. Can you talk to someone at school (teacher, advisor, counselor, etc.) about dealing with the missing assignments? If you let them know how stressed out you are, they may be willing to make some kind of accommodation to let you catch up.
I was in the exact same position as you a few semesters ago (lots of missing assignments, feeling hopeless, stupid, and suicidal), and let me tell you, it gets better from here. I know that most people never act on their suicidal thinking, but if you are seriously considering hurting yourself, please get help. I really considered ending my life over my school struggles, and now I am so glad I didn't. Take care of yourself. Things WILL get better, no matter what happens with your assignments.