Oops, busted!!

Getting to be a pattern:  No seats available on 1-3, so sit in at 1-2 while waiting and make money.

I won two big hands right away and was $150 up when they called for my 1-3 seat, so I happily took my profit and left.  Then I sat down at the new table and promptly got busted when a guy with 7-8 raised pre-flop and I got it all in with Top Pair Top Kicker (TPTK) on a flop of 7-8-Q.  I also ran into a Flush on the Turn that I didn't believe and gave away a total of about $450.  Not a good day.  I still need to stop and think whenever I want to put in a lot of money on a one pair hand.  Yes, I have to protect my hand, but I need to figure out how much protection costs and how often to pay off someone who is betting like they just drew out on me.