pregnant??????

so i had sex for the first time about 3 weeks ago and again about a week ago. both times we didn’t use protection and both times he didn’t cum inside me, and the only possible way that me and my boyfriend can think of is when it was on my lips and he kissed me and went down on me. but he didn’t have like a crazy amount on his lips and he licked them and then went down on me. and now i am late for my period which i am late sometimes but now the pressures on. although i’ve been extremely stressed lately especially since my boyfriend and i have been getting into arguments a lot recently and my sleep schedule is complete messed up since i usually don’t go to sleep until about 3-4 am and wake up at 12-2 and then take a nap at 5-7 which is normal for me in the summer though. i’ve read that u can miss your period because of stress so what do u guys think, am i pregnant or just stressing out about it and missing my period? (i’m 15 btw)