1/2 is definitly too small on the turn. If you want to vary them(which is unnecessary at 25NL) then you need to vary them between 2/3rds and PSB. When the board is this drawy you must bet 3/4th or more of the pot. As played I think I fold because you have to be ahead more than half the time for a call to be correct. I don't think that you are. QJ does make this play though as do some bad players with two pair who just dont want to let it go(makes no sense I know but I find they do this a good bit).

Note for those of you who don't know me: I generally play $200NL to $600NL(sometimes $1000NL) so I dont have a lot of experience at this limit.