Betta Fish: Is this normal?

Everytime I walk in he’s laying like this or by the corner laying like this, even caught him on his side one time. The first week or so he would lay on the leafs or look a lot more “awake” while he rested and now he’s scaring me. He still swims around like he’s happy when I make him wake up, he’ll normally go make a bubble or two after I wake him up. The pet store told me his water was fine and I didn’t need to change it yet but it had a little ammonia and a little bit of nitrates so I did like a 25 percent water change, which he seem to love at the time and afterward. Fast forward a day or two and he’s laying like this most of the time. Not sure if this is normal or not but he’s starting to scare me.