Smoking and pregnant

I’ve just found out I’m pregnant only about 4 weeks and it was a surprise not planned but I feel so guilty and worried because recently I’ve been treating my body badly, smoking and eating next to nothing and hardly sleeping at all, I had a mc last year and I’m so scared I could’ve harmed my baby I know I’m early on but I’m scared obviously I’m changing my behaviours right away now I know but do you think I could’ve already harmed my baby?

Also I obviously haven’t been taking my folic acid since we didn’t plan this 😭