pregnancy scare

I just got the Depo shot while I was on my period last month and people said it works immediately so me and my boyfriend fooled around. we did not have sex but I’m scared that precum could’ve gotten on his fingers while he fingered me. I am now 4 days late on my period and I took a first response pregnancy test first thing this morning and it was negative. ive been having weird cramps and feeling sick. plsase dont be mean or judge or say i need to educate myself im just scared. thank u