Advise ??

Yesterday morning I tested positive on a opk then negive at night however my CM is still watery like yesterday. also today I keep getting AF like systems e.g lower belly pains on and off.. my lower belly has ballooned out .. I keep thinking I my just need a wee but nothing is coming out ha I'm guessing I'm 1dpo as it was yesterday was positive .. P.s I'm new to all this so opinions would be great full ..