ercer

my age is 20..my query is about erectionsErection problems & wet dreams....are they normal..??
also,,i do ve 1 friend of mine in college which i consider as my sister,,sometimes when we are together in college n having fun,,i get to see some cleavages(i.e. view under her top etc..)by chance..n get excited(erectionsErection problems) n enjoy it n watch it till m able to..bt when i get normal and think about it later i realise that although she's a girl,,but i consider her as my sister..so i feel guilty later on about viewing inside her top n etc..it sometimes puts me under depression thnking that is it normal to happen..??or something wrong is happeing..??plzz replyy