I'm currently studying Mathematical Science and I found that it's hard for me to comprehend mathematical concepts without anyone explain them to me especially complex analysis and differential equations. I can spend days or weeks just to solve/prove a mathematical problem which most of my friends can solve it within 1 hour. My current CGPA is 3.0. I love mathematics and really want to pursue pure mathematics but my progress is just too slow compare to others... Now I doubt my ability and I'm really depressed... What should I do? Should I continue master or phd? Or just give up my dream?