Shouldn't have grabbed that pawn

I took a free pawn on move 7 and was punished for it. My opponent played a line against me that I hadn't faced, and of course, I had no idea how to handle it. This was an OTB game, 105 minutes with a 5-second delay. Time pressure was not a factor. I would like to know what I should have played on move 7 and whether there was a way to save the game once I got into trouble. I have not done the computer analysis. My opponent bought me a soda at the hotel lounge after the game, and that was the only thing I got out of this game.

That was very kind of your opponent.

In my opinion, the problems began on move 6 when you took the bishop, you should've just castled short. King safety is more important than that little pawn on c6, but it got worse when you castled long, and black had that open c file because you decided to take the pawn. However, I don't know where else you could go with your king. Why? Because you took the bishop on h6 and allowed the queen to attack your weak dark squares.