Why it is happening with meeeeeeee

Why it is so hard for me to understand a simplest thing , I am feeling so depressed today , I have insulted myself for not understanding a simplest thing , my prof and my classmate looking at each other faces like smiling and laughing, thinking I am so dumbbbbbbbbbbbb , I can't take this anymore , everyone are so smart here , why i am so dumb , since 7 to 8 months I have only insulted myselfffffffffff, I can't face anyone, that my guy frnd always thinks that I am so dumbbbbbbb and now what I have doneeee now , I can't face anyone now , please god help me.

I am feeling so nervous , so depressed due to this , what shall I do now , what impression I have made of myself in front of these people , to whom I have to study for more 2 years , I can't take this anymore, whattttt shalll I do nowwwwwwwwww