problem peeing

Okay so i'm 11w 2d for the last two weeks i've had a difficult time getting started to pee, especially for my first potty of the day. i have to push hard to get the stream started. (and i usually don't even have to think about it, i just sit & go) one morning no matter how much i pushed nothing came out & it freaked me out. i stood up and moved around, jumped, squatted, leaned forward & back, tried again... still nothing, yet i had a full blatter. i was so scared i was 2 seconds away from calling someone. but thankfully i was finally able to go. i don't have a problem emptying my blatter, just getting the stream started. has anyone else experienced this? all my lab results just came back negative/normal so i don't have a UTI or anything. i wonder why this is happening, i'm going to obviously mention it to my OB during my next appt in 4 days, but just wanted to know if anyone else has experienced this, is it normal?