NL100, TPGK, how to play??

[StyloAl]

No-Limit Hold'em, $1.00 BB (6 handed) - Hold'em Manager Converter Tool from FlopTurnRiver.com

SB ($109.38)
Hero (BB) ($105.05)
UTG ($19.65)
MP ($100)
Button ($174.73)

Preflop: Hero is BB with J, A
UTG calls $1, MP bets $4.50, 2 folds, Hero calls $3.50, 1 fold

Flop: ($10.50) 3, A, 9 (2 players)
Hero checks, MP bets $7, Hero ???

called man da pre? denk 3 bet ist nicht so gut oder? fold eher zu weak oder nicht?

raise flop for value and protection or what is to do?
wenn nein, warum und was macht man vs 3 barrels z.b??