I still feel bad about this but let's start with a quick rundown of the incident.

I play hockey (the field one) and was practicing a bit in my yard. My cat usually goes inside when I do this but this time she apparently did not. I hit the ball, not super hard but it did go with a speed that would make me go ouch if it hit me, and it rolled past my intended target into the bushes where apparently my cat had been hiding.

As soon as I hit her she sprinted away, I've never seen her go that fast, and hid underneath the staircase in the basement and did not want to get out or get petted for quite a while. Now that she's out she does not want to eat, not even her candies, which surprised and worried me since she has a rather large appetite or get attention and is scared quite easily.

When she finally let us touch her she kept her paw on the same spot on her belly and did not want us to touch her there. This makes me think that I hit her there and I am clueless as to what to do now.

In humans a punch to the stomach can give some serious complications and even though I would have been fine if that ball hit me in the stomach she is a much smaller and older cat.

My most important question is should I take her to the vet. I don't want to cause any unnecessary stress or anything but I am afraid that she might have more serious injuries than she shows. I'm mostly concerned due to the fact that she has not eaten anything since this happened, which was over 2 hours ago, and it's quite a bit past her usual 'dinner time'.

I hope you guys can help me out with this because I really don't know what to do.

--EDIT--: talked to vet and he did not see a reason to immediately rush over.