is it normal to be sad after?

for context, i’m not experienced and i have a friend i’ve been messing around with. i like him and he’s nice but as soon as it’s over i just feel sad. the sex itself is okay, but immediately after it’s like i see my future and it says “this is all anyone would want you for. like that’s it, just sex that i don’t enjoy that much in the first place. sometimes it feels like i’m just doing my friend a favor. it’s not the guy’s fault. i really don’t mind hooking up with him. i just want to stop feeling all this random dread right after.