Why am I So Stupid?

So, I got together with my 430w group tonight to work on the robot. We were there until after 3am. I feel generally useless to the group since I contribute so little to actually building and programming the robot. I just don’t know what to do and I don’t know how to do anything concerning the robot. I feel so embarrassed sitting there looking stupid and barely helping out, but I also feel to embarrassed to ask them if there’s anything I can do. Because I’m afraid they’ll give me something to do that I don’t know how to do then I’ll feel even more stupid. Then on the way home, Kyle told us that he has a 3.6 GPA even though he drinks himself stupid all the time and that made me feel even more stupid. I barely have a 3.2 now and I never drink. I struggle with all my classes and I always feel overwhelmed in them. Why am I so stupid? :(:(