DM burnout immediately after a hiatus

Hello, I’ve been DMing modules since April 2023 and co-DMing a custom campaign since I’m guessing October of 2023, all on Roll20, roughly every other Saturday. I started DMing to give another DM a break and so our group could still get together and play something. There have been breaks for holidays and life events, but it was pretty consistent until April of this year. Around April, one player quit and I had begun to move apartments and another of my players took a long family trip. The player quitting unexpectedly hurt my feelings because they said they were not having fun. I didn’t want to run the final session before our break because it had rewards for every character and a mini boss with a lot of treasure at the end that would have acted as a good stopping point. I let my co-Dm know and he said he understood and recommended we let the party know the situation and that we would try to find another player and reconvene as soon as possible.

In July, we found a new player who was going to be available at the end of the month to start. We let the rest of the party know and asked availability. A date was decided on that all but one player could meet so we did a little in world one-shot set a few hundred years before the regular campaign to provide some lore and allow everyone to try something new for a session without a lot of stakes.

While it was nice to have everyone together again, one of my longtime players was taking the game very serious and was very critical of choices I made for a few of the enemies turns. I’ve known this player for a long time and he used to dm a campaign I was in until scheduling became too much of an issue. Him being critical made it hard to stay focused on DMing and having fun and I’m not looking forward to our next regular campaign session. I miss getting to play dnd, DMing no longer feels enjoyable it just feels like an extra job. I don’t know what to do, part of me wants to just say I’m done and part of me wants to stick it out and see how it goes for a couple of sessions.