please give me some hope and advice

Heather
I am 17.. This morning around 1 am I had sex. My friend came on my back and put his dick back inside of me right after, from behind. I got back home checking myself out being curious as always, and this cum inside me was not mine.. but also he had spit in me earlier that night. I'm out of town and can't go get a plan B. It's super awkward to ask. But I'm already freaking out I want to stop having sex bc of all the scares but it's addictive. Please give me some words of hope to hang on too.