I'm an undergrad and I will be completing my Master's Thesis the next year,based on elliptic curves.However coming to the end of my undergrad career as math major,I don't feel the same enthusiasm I used to feel in my early years.I don't seem to remember the concepts I learnt a year ago(Galois Theory and Algebraic Topology) as well as I did then.Recently I met with my supervisor and was faced with a very basic question which I knew the answer for but was not confident enough.I'm not someone who goes after grades but focuses on inuition and understanding the concepts well.I've learnt theorems,solved exercises well and understood those a year ago and now I feel embarassed to not recollect the concepts(which are core to advanced mathematics) I've learnt 10-12 months ago.I can always go back and read them again(faster of course) but the point is:-
1.)Why does this happen?Is it normal and happens to everyone?
2.)Nowadays reading math books seem like a chore to me,does this mean I not really interested in the subject anymore?Am I actually doing math the right way?
3.)This does not happen when I keep using concepts from,say,commutative algebra.And so is it important to remember all the concepts if I don't use them so often.
Need some advice and insight on this.