Advice Please.

August 4 I give a hand job and can’t remember if the guy pre-came or not I know for sure he didn’t cum but after the handjob i fingered myself I’ve tested on the 4th week September 1 and it came back negative am i in the clear? My periods are usually irregular and my cycle days from what the obgyn estimated is 38-50 days. Anything helps please i’m stressing out.