mixed emotions

guys i need help i’ve been talking to this dude for about three weeks.. he’s already so clingy and he wants something real and i told him the same thing and i noticed that i think i want to be single cuz when i’m with him i’m having fun but when i’m not i don’t miss him as much .. i feel like it’s too late to back out bc idk how to tell him i want to be single in a nice way.. i feel like ima regret this it bc he’s a good guy . i just have mixed emotions .