Hey! I know this is not a particularly complex hand but it's a situation I find myself in way too often and I'm never really sure what to do.

I decide to flat instead of 3-betting because J9s flops well. (I'm not sure if that's profitable if I'm just going to fold to a c-bet everytime I miss the board?)

I make second pair but I have no information on the other guy at all and just end up folding because his cbet feels too big for me to continue out of position with second pair. This feels like a horrible play but I don't really know what else to do. I assume he's very likely to bet the turn if he already bets two thirds of the pot on the flop so I decide to just lose the least amount possible instead of calling once and folding the turn anyway.

How should I be playing these spots?

Hope someone can help!