Fide rating versus online rating


Blitz and over the board tournaments are very different. Your tournament rating probably reflects a lot fewer games than the 1234 blitz games you have played.
How many games is your FIDE rating based on? In the US, a rating is provisional until you have played 24 games. You may not have found your real rating yet.
Furthermore, don't worry about the difference between the two ratings. Ratings are correlated but they aren't measuring anything absolute, like the temperature that water boils.
Good answers here. Blitz is not the same as 45 minute games. Very different skill set. And focus more on learning instead of worrying about rating, though of course we care about our rating. I bet if you hit 2000 in a month, you would be here worrying if you slid back to 1700.

This article will probably help you to find the answer. But since you're not a high-rated player you don't need to worry about it all. Just play chess and enjoy yourself.
https://www.chess.com/forum/view/general/fide-ratings-vs-chesscom-ratings-explored

I'm 1828 blitz rating on this site over a large sample size (2000 games), yet my FIDE rating is only 1245.
Chess.com is definitely inflated.