Im 18 weeks, since few days i feel the baby moving sometimes in a day. but from 2days i cant feel any, i ate outside food. should i worry?

Probably ok: No one can guarantee that there isn't a problem, but it is not uncommon at this gestational age to sometimes not feel much or any movement for a period of time. Many times the baby is moving and you just aren't aware. Because you are about 6 weeks away from the time the baby could survive outside of the uterus, there isn't really anything we can do. The food is likely not an issue.