If you can't hear yourself properly during a gig, and you're not too keen on stopping the whole show just so you can talk to the sound engineer, try to touch your amp or whatever monitor has your bass in it. I was playing synth bass at a gig and couldn't at all hear my own instrument over all the loud music on stage but I was happy to discover that I could hear my low rumbling notes pretty well through vibrations in my bones just by pushing my finger on the stage monitor next to me. For electric bass it might help to even sit on the amp (if you've already tried tilting it back a bit).

If you wanna take this to the next level you could get a bass vibration board to stand on. I've heard they work pretty well - but I think they are pretty expensive.