How many buy ins can one lose with under flushes?

[Digital Entropy]

I'm still relatively new to poker but consider myself a knowledgable player. Four of the last six flushes I have made have been under-flushes. One flush was beat by a single over, but the rest were a better both suited cards hand. And worse, I pressed them very strong. Am I going too far with my middle suited connectors when I flop a flush draw? I've noticed a pattern of opponent bet 1/3 pot, I raise to 4/5 pot, then opponent calls on flop. Does this line mean "I'm holding a suited ace" every time?! Noticed this at different levels ...less in the higher the money level as preflop raises tend to scare the suited aces out.

Six max, NL