KK played very weak

Need some thoughts on this one...Yuck.

Pacific poker .. $25NL .10/25 blinds, 8 handed
Hero has $45
Villain has about $33

Hero is dealt: K[img]/images/graemlins/spade.gif[/img]K[img]/images/graemlins/diamond.gif[/img] in LP
4 limpers
Hero raises to $2
MP calls, rest fold.

Flop: ($5) 2[img]/images/graemlins/heart.gif[/img]3[img]/images/graemlins/heart.gif[/img]8[img]/images/graemlins/diamond.gif[/img]
MP checks
Hero bets $4
MP calls

Turn: ($13) 7[img]/images/graemlins/diamond.gif[/img]
MP leads for $2.50
Hero calls

River: ($18): T[img]/images/graemlins/diamond.gif[/img]
Villain pushes all in (about $13 more)
Hero folds.

Thoughts? This felt very weak, and I felt uncomfortable against one of the larger stacks.

Preflop:
Standard

Flop:
After he checked and I bet 3/4 pot, he called immediately

Turn:
What's with his small bet here? Raise and see where am at? I think my call here was awful.

River:
Given the action, do I have to call this?

Man was this a stupid hand.