Kinda freaking out

So my boyfriend and I had sex for the first time without a condom since I had my son in July. I got the depo shot but I can’t remember exactly when I got it. But I was on top and he came inside me and I’m freaking out because I’m not ready for another baby. When I got the shot it was the very first time trying the form if birth control I used the nexplanon implant and switched to the pill but forgot to take it and became pregnant with my son. I’ve been bleeding for over a month now and recently it’s only been light brown spotting. But this morning there was red when I wiped after I peed and it has been throughout the day no red blood any other time today except right after I pee. Am I starting my period or what is going on? Should I be worried about being pregnant even though it was just last night? Ugh help ladies.