$100NL 6-max @ Tribeca

i raise [Td] OTB to $4, BB calls. $100 effective stacks. BB is decent, aggressive, picks good spots to bluff/semi-bluff. we've been going at it and he's generally been winning. mostly just bad luck on my part. but he's been running me over a little.

flop: [2h][2c]
pot: $8

check/check

turn:
pot: $8

check, i bet $6. he calls.

river:
pot: $20

he leads $5, i make it $15 (questionable, i know). he thinks for about 10 seconds and then makes it $55.

can i call this? my hand is weak but his line looks like bluff.