23 year old woman having trouble urinating after abdominal surgery...embarrassing..?

I had abdominal surgery last Tuesday. Ever since then, it seems like I've been having trouble urinating. I feel like I really have to go, I get to the bathroom & I sit down & it takes about 10 seconds for me to start going (normally I would start right away). Then It only trickles out a little bit, there's almost no pressure. I haven't really had any pain at all besides minor menstrual cramps (I have my period). What could be wrong?? I go see my surgeon today for a post-op appointment & I'll obviously say something. I have been taking Oxycodone (10mg percocet/325mg acetaminophen) since before my surgery for maybe like 2 weeks & I've been on 15mg Roxocodone since the surgery. Not really sure if that has any significance. Any help would be appreciated.