If he's laying on his side it could be a swim bladder problem. Try giving him a pea. Just get some fresh or frozen green peas and put them in boiling water for about a minute or two and then let them cool. Take off the outer coating and cut it into really small pieces and toss some in there (one by one so you won't have it raining peas in the tank ). Most bettas love them
peas really help their digestion, so give him a bit to digest and pass them. He maybe just full. Mine loves peas, chomps them quick but only a couple of bites then his little tummy is full. Hope yours recovers fast!
Id probably abstain from feeding for more like 3-4 days, then feed a pea on the fifth day, then fast for one day, then resume feeding normally. Good luck!
Another case of swim bladder! You need to immediately lower the water. The biggest threat right now is of drowning/suffocation. Just enough water for the fish to stay wet but not have to work to get air. There are other things you can do to help but the most important is lowering the water. I'd also recommend not feeding until he feels better.
I'm just about to post my ordeal today and my method of treatment (other than lowering the water) in case you want to check out my post.
yes he has about 3 in of water now and he dosent have to struggle for air he cant get to the bottom of the tank even so i dont think we have to worry about that but thanks for the advice