Is this an example of where we need that level two/three thinking?
What does my opponent have/what does my opponent think i have.
Your bet here looks like you have tpgk. Thats what he sees (hopefully anyway) thus when he pushes over the top of you it could mean two/three things.
1. hes bluffing (unlikely at lower levels where i (you too?) play) people simply dont bluff or when they do its readable.
2.He has a hand that beats your tpgk and has pushed hoping you call too attached to your top pair. (as they say. Never bet the ranch on top pair)
3.He has a draw to the nuts and enough outs to make it worth it (or in a fishes case he just has outs to the best hand probably not enough odds though)

Then i'd consider what he might have called,but not rasied with preflop.
A pp is a very good probablilty. If your heads up then he should have raised to protect his hand. An over pair is another possibility eg 9s but again maybe a raise would be expected.
Quite simply if someone goes over the top of you stop. think. think of the hands that may beat your hand. consider the opponenst style (tight,manaic) make a decision.Unless you have the nuts at that moment or a strong (better than TPTK) hand you have to fold and show respect. DOnt worry about being pushed around. Hopefully he'll do that when you have the nuts and get busted.
Here you have to consider what your opps play suggests about his hand. It wasnt good enough to raise but post flop its good enough to be all in. That looks like set/two pair/overpair imo.