u shouldnt have been climbing at 20 degrees flaps, maximum permissible in a climb is 10!
And what about your minimum retraction height? When flying the 152, I was always taught the following. To perform a go-around apply full power and immediately remove the drag flap (30-20). Under no circumstances must you retract the flaps any further until you have reached your min retraction height (normally 300ft AAL).
We performed a go-around from the flare due to a rather long float. I thought the climb to 300ft with flap 20 was rather slow.