Since I don't know the specifics of your situation, maybe I'm projecting, but I'm thinking there are (at least) three different smaller pieces to this problem, and it might be helpfully to work on each one of them separately. My initial thought is that the smaller pieces might look like this:
1) "leaving the house"
2) interacting with people
3) getting overstimulated in public (you might describe this third one in different terms or say it doesn't exist at all or is something completely different than this--see if you can come up with a #3 that is related to what you are feeling when you are on your dates).
So for example, for #1, the first step is just to go out the door, stand there for a minute or two, then go back inside. Gradually add time and distance from the house. Like walk down to the corner and back and add additional distance a little at a time. Or walk to your car and back. Then add getting into the car and getting out again. Then add getting into the car and driving around. Then add making a pickup order, driving to the store and picking it up and going home. Etc.
For #2, you could call a friend and talk to them on the phone (or facetime or skype or zoom) at first. Like do it every day. Then maybe arrange to have them come to your house for coffee. First just one person at a time and then two. IDK.
Possibly after you work on those first two, the third one (related to being in public) will already be easier. Otherwise, work on that a little bit at a time. Like make a pickup order, but leave early. When you get there, go inside and buy one item that is close to the cash register, then leave and get your pickup order. Gradually extend how long you are in the store (by buying additional items and/or items further from the cash register, for example), so you will eventually be able to shop in the store instead of doing a pickup. Once you can handle that, going to a restaurant might be easier.
Again, I don't really know the specifics of your situation, but perhaps you can look at this and use it as a springboard to come up with specific things that apply to you. I really do have the impression that the best thing to do is work on smaller pieces of the problem.
Also? I don't think you are having psychosis. I think this is just a thing that can happen after there's been a pandemic if a person has already been having some problems.
P.S. If any of this is resonating for you, it might be helpful to try to assemble a little bit of a "support group" (perhaps here) with other people who need to extend their comfort zones in some way. Basically some (at least two) people just checking in with each other to say, "Hey, I did leave the house today!" (or whatever). Or you might see if one of your IRL friends would support you (in a distanced way) with check-ins. That can be very helpful.
