Can I get Pregnant from this experience?

So my boyfriend and I were having anal (we are both std free) and he ejaculated inside of me, after about 30 seconds he pulled out and i stood up and panicked that it would leak out so minutes later i went to the bathroom and tried to get all of it out which i think i did because liquid came out in the bathroom and i was very careful of how i wiped it, however there was brown liquid on my underwear afterwards could this possibly be leakage?? could my vagina absorb it and get pregnant? i went and changed my underwear as soon as i noticed but i hope i wasnt too late and also keep in mind that i just finished my period and am not ovulating or fertile. Do you think i could be pregnant? The internet says that chances are very slim but i always worry a lot, thankyou everyone please help!! I will be more careful next time