a few month ago, I was also new here and came to the forum with exactly the same problem. My post on that is called "Dealing with the end of the series", you should be able to find it just a few posts below yours.
I just wanted to say that I really feel you and what you are going through at the moment. I know, it is tough, especially as you're thinking about the show all the time, missing the characters and feeling a kind of emptiness inside of you. Well, it took me two to three weeks to get over it and move on, right now I am stuck on another sitcom. It was a good idea to ask this forum, there are some kind guys here that do literally nothing else but talking about the show all the time. That may help you. As well as that, you should go and meet some family or friends using social media and tell them about your feelings, as you're quarantined that should be the best solution
I wouldn't advise you to rewatch the show immediately, take a break of at least a month or so and after that, start again if you feel like doing so.
If you still have questions or just want to talk, the forum is here, open to you.
Greetings from Germany and Merry Christmas,
Thor and Dr. Jones