Im worried, is my puppy sick?

[Judy]

My puppy is 7 wks old, he is very playful nd loving. However, for the past 2 days his belly has been swollen nd hard, I plan to take him to the vet soon for him to get his shots, but Im starting to worry that he is sick nd needs to be addressed right away. His belly is the only prolbem that he has, other than that he is a playful little puppy. Not sure if this matters or not but he is mix: husky, lab, nd retriever