my chess skills are deteriorating


Basic opening strategy needs to be tuned up. Looks like you create weaknesses with even material. Chessbrah habits on YouTube could help.

I'd say don't be too concerned. I was recently concerned when I was at 850 and fell to ~700 a month ago. Now I'm 1000! Try to ask yourself before every move if it's a blunder, as that's likely how your losing most of your games. Your opponents will blunder, so if you can minimize yours, you will likely quickly increase your rating. Good luck!