One Week Old Kitten Has A Swollen Tummy, What's The Problem?

Kitten was found in the middle of the road age 1 or 2 days old she is now a week old and she is very active and has a vary swell'd tummy as well but a don't know if it is normal. She eats, pee's and poops ok. 2 days ago she started to snezz and crying alot too.