Had several situations today where I would find myself wanting to raise preflop in late position with what I would consider a marginal hand (example 99, 88, 77, AQo, AJs) but getting raised before me. I was flat calling, not hitting anything on the flop and then throwing my hand away.

Flat calling to me means "I might have a hand but I'm going to see a flop to check things out." Reraising means "I have a hand I'm going to try to isolate you with" and then c-betting can land a pot.

In these sorts of situations since I was planning on raising anyway do you flat call the raise, fold to the previous raise or reraise? I know it depends on the read whether or not you would reraise, but what I'm wondering is if flat calling in these situations is -EV.