am i pregnant? missed period on pill, no sex?

24 days ago me and a guy were messing around. we did not have sex but i gave him a handjob. he did not ejacukate but there may have been some pre ***. a few minutes later i touched my vagina. i am on the combination pill and i take it every night but sometimes 4-5 hours late. now i am a day late on my withdrawl bleed and my boobs are a little sore and seem larger. i took tests 19, 21, 22 and 24 days after and they were all negative. could i be pregnant?