https://support.chess.com/customer/portal/articles/1444777
Check out the part about the Rating Deviation (RD). As a new player your RD is high since your ultimate playing strength is unknown. Your upward and downward rating swings will be larger until you have played enough games for your rating to get close to what your performances show your rating should be.
The more games you play, the lower your RD gets and the less drastic your point loss/gains will be.
I started with 1200 ELO. I lose the first macth and my score was 1084 (-116 points!). I lose another match and now my score is 1000 (-84 points!). Is it correct?