Topspin problem

Hello Sir 

I wanna ask you for a problem that i m facing now a days in my game i am a right handed attacking type of player but i am having problem in executing my third ball attack its not an issue in past but now whenever i serve to my opponent now a days he returned it by chopping it the balls height is so low that i cant differentiate either the return is with under spin or its a floater due to which my forehand attack isn't as good as it was before i tried to make a loop but the ball goes straight out of the table Tell me that how can i feel the difference between floater return and underspin return so that i can attack the ball in  good manner and also tell me the racket angle for attacking both balls.

Note If theres any serve i can try on my opponent then do tell me he is a right handed player too.