[paradroid12]

I'll be really detailed, just for fun...

Sounds like the basic east coast $2/5 game: limp, call, fold. You should raise PF to $30-40. Any outcome you get here is favorable: 1. a multi-way pot with the best multi-way pot hand there is (JTs) on the button; 2. heads up in position against something marginal (meaning you can safely CB just about any flop); 3. take down the $20 with 0 risk. If you get RR pre, you can dump it at minimal loss or play implied odds and try to crack a big pair for a huge pot (and you have a good hand to do it).

Call flop unless you have a good read on SB. The first position bet at an unraised rag flop usually is strong (read, he wants you to raise). Plus there are a lot of turn cards that can help you: 7, 9, 10 (though it makes another straight), J, and heart.

Also, since you failed to raise PF, your hand is transparent. It looks like overs with a draw. The only hands SB could put you on are A8 and 44, and maybe 6s. Not sure how you play, but I'm guessing you raise PF with 8s in this spot, and also maybe with 6s. So ... when you raise the flop, you're playing your hand face up, and you can be sure he's got at least 2p when he's pushing over you. You have to call for the pot odds, but taking an uber-cheap turn would've been much better.

In answer to your questions:
1. You played weak PF and donked the turn.
2. Instacall, but if you brick out, you kick yourself for putting $250 into an unraised pot (with only $40 dead) against a real hand when you were just on a draw.
3. This is something you should be thinking of BEFORE you say "make it $100." As Doyle says, don't go broke in a nothing pot. You succeeded in pricing yourself in on your draw, but at the end of the day you put $250 into a $600 pot on a J high flush draw. No bueno.

I hope you got there though.