I screwed up what should I do now?

My son just turned 28 months. This past summer he started taking about the potty. So we got him a little potty and he loved to sit on it and read books. We didn't force out and itprobably took a good two months before he ever peed on it.By december he's consistently going pee or poo when we put him on the potty.
For the last 2 months he averages just 1 or 2 wet diapers per day. We have been putting him on the potty every 2 hours and he usually stays dry in between. However he almost never asked to go.
In the last 2 weeks he started announcing my diaper is dry or my diaper is wet. He also transferred to the preschool room at his daycare. Since this move he's been talking about which kids wear underwear and trying to.put on pants without a diaper. Today I put him in underwear fully expecting accidents.
Imstead on 2 separate occasions he went into the washroom refused pull down the underwear and refuse to sit on the potty and then stood in an area away from the toilet and peed or pooed on the floor. The first time I asked him if he knew where he was.supposed.to pee or poo and gave him the option of putting on underwear again or not. The second time he did.this I lost it yelled at him and put him back on a diaper. I know I messed up but I never expected he would intentionally go on the floor. Do we go back to underwear, go back to diapers and trying every two hours or back off entirely for a while?