Heated- Yes, but I don't have a thermometer yet. I am getting one tomorrow.
Filtered- No, but I do have a bubbler that seems to scare my betta. I only leave it on for about an hour a day so the water doesnt go bad.
And by the way, this is my tank:
Anytime you have behavior changes even if you just made a water change...make another water change to rule out the water/environment as the cause.....it can be easy to forget dechlorinator or not use enough, something on your hand or the air....anything.....water only changes will not hurt regardless......make sure to use dechlorinator and to match the water temp between the new and old water to prevent shock issues...
Update! All is well! I checked on my MS lest night, he pulled into his shell. Now is very active an moving around. And BTW is it okay for him to be climbing the heater?? It's not super warm or anything. It only turns on when it needs to.