You know you're playing against a donk when...

I don't understand what I'm doing wrong:

PokerStars Game #6635006873: Tournament #33720836, $10+$1 Hold'em No Limit
- Level II (15/30) - 2006/10/14 - 19:54:48 (ET)
Table '33720836 1' 9-max Seat #7 is the button
Seat 1: ThePinkMan (2040 in chips)
Seat 2: 1tipper1 (1425 in chips)
Seat 3: BigHeeb91 (1485 in chips)
Seat 4: mthoss (1200 in chips)
Seat 5: rkjmsbtch (1255 in chips)
Seat 7: jkimmeli (870 in chips)
Seat 8: TexasFredos (3220 in chips)
Seat 9: S Trump (3385 in chips)
TexasFredos: posts small blind 15
S Trump: posts big blind 30
*** HOLE CARDS ***
Dealt to BigHeeb91 [Qd Qs]
ThePinkMan: folds
1tipper1: calls 30
BigHeeb91: raises 160 to 190
mthoss: calls 190
rkjmsbtch: folds
jkimmeli: folds
TexasFredos: folds
S Trump: calls 160
1tipper1: folds
*** FLOP *** [5h 3d 2s]
yang123yang is connected
S Trump: checks
BigHeeb91: bets 500
mthoss: folds
S Trump: calls 500
*** TURN *** [5h 3d 2s] [5d]
S Trump: checks
BigHeeb91: bets 795 and is all-in
S Trump: calls 795
*** RIVER *** [5h 3d 2s 5d] [5s]
*** SHOW DOWN ***
S Trump: shows [5c Kc] (four of a kind, Fives)
BigHeeb91: shows [Qd Qs] (a full house, Fives full of Queens)
S Trump collected 3205 from pot
*** SUMMARY ***Total pot 3205 Rake 0 Board [5h 3d 2s 5d 5s]
Seat 1: ThePinkMan folded before Flop (didn't bet)
Seat 2: 1tipper1 folded before Flop
Seat 3: BigHeeb91 showed [Qd Qs] and lost with a full house, Fives full of Queens
Seat 4: mthoss folded on the Flop
Seat 5: rkjmsbtch folded before Flop (didn't bet)
Seat 7: jkimmeli (button) folded before Flop (didn't bet)
Seat 8: TexasFredos (small blind) folded before Flop
Seat 9: S Trump (big blind) showed [5c Kc] and won (3205) with four of a kind, Fives

I just don't understand why people defend their blinds with ANY TWO CARDS. And why is it that every time I pick up a big pocket pair, I raise, get called, flop the overpair and continuously get sucked out on??

I rasied preflop 3 1/2 x the BB... there's no reason to call that raise. And then when I bet that much on the flop, I OBVIOUSLY have an overpair, right? He had to have called thinking his pair of 5s were good, right? What did he put me on betting that much? AK? ARGH!!!