Anxiety Support Group
Anxiety is a physical condition marked by intense and persistent feelings of distress, fear, angst or dread. General anxiety caused by routine day-to-day stresses usually passes quickly and is experienced by almost everyone at one time or another. However, such feelings that linger over time and are very difficult to cope with, and which lack a clear cause, may indicate...

Change your pattern of thought.
You can do this!
I'm sorry you're going through school problems. Your struggles do matter even if other people's struggles seem worse. Each person is at a different point in life, so it's unfair to compare yourself to others in this way.
I have also been struggling a lot this year with school, so you are not alone. This year has been especially rough for me because I went through some trauma. I also felt it was hard for me to go to school. I started missing a lot of school because some days I had no energy to do so and would prefer to stay in bed. I'm still healing right now, that's for sure, but I have been getting better--just at a slower pace than I'd prefer.
Going through these experiences has taught me that I have to be patient with myself, even if my slow progress is frustrating me (it still does, all the time). Please be patient with yourself. It's okay to feel crummy; that's just the process of getting better.
Would it help relieve your stress if you told your teachers about your struggles? I understand if you're unwilling to, because I also felt that way earlier this year. I got to a point where I was unable to complete homework on time anymore, so I had to email my teachers to let them know what was going on with me. They were understanding and supportive of me. Letting your teachers know about your situation would allow them to understand what you are going through, and some of them might give you some leeway for turning in assignments late (though, I can't guarantee that). If you are uncomfortable talking to them face-to-face, you could always email them. It makes me anxious to talk to people directly, so emailing my teachers really helped.
One of the reasons why your teachers and friends keep on getting upset with you is because they don't know about the struggles that you are going through. Often when people get to know what someone is going through, they are more empathetic to that person. Try opening up to someone at school or out of school and talk to them about your situation. I know that takes a lot of trust, and it's okay if you don't feel ready to do that. It is bad to bottle up all your emotions and feelings, and you need an outlet to allow yourself to feel better. Talking to someone else is not talking a step back--it's not a sign of weakness. In fact, it's a sign of strength because you are recognizing that you are struggling and want to help yourself get through this difficult time.
You may not think you'll get through this, but I have faith in you. Please be patient with yourself, and good luck!