Pleaseeee help!!!!!

So about 2 and half weeks ago me and my boyfriend/fiancé of 2 years split. I moved out of our house into my parents until I get back on my feet. I had went out with some friends to get my mind off everything and got really messed up and we all pitched in on a hotel room to go back to at the end of the night . I ended up hooking up with one of the guys that came back with us. Needless to say he came in me but didn’t think too much about it cause didn’t think it was during my fertile window. Th next morning I woke up and checked eve to see when I was supposed to ovulate and apparently it was that day! (The day right after we had sex) 😳

It’s been four days and I just went to the bathroom and I’m spotting it’s light pink and now I’m so paranoid that is implantation bleeding. I’m cramping but it’s not as bad as when I have period cramps. Someone please help.