Oh shelaghc, I'm so sorry you're having a tough time. Caring for a sick kitty can start to wear on the caregiver, and it can be easy to isolate ourselves in an effort to give our kitties the best possible care.
It really is okay to give them their food, put them in separate rooms, and leave the house. Put one in the bathroom with a litter box, one in the bedroom with a litter box, one in the living room, and then just go somewhere. They may well figure out how to eat on their own if they know you aren't going to come rescue them from misshapen food

. If you have any plastic storage tubs in your house, they make perfect extra litter boxes when you need one.
It can take some problem solving, but I've found that 99% of the time, when I think there is a problem that is stopping me, it's really something that can be solved. Maybe not perfectly, but good enough.
I reached a point recently where I was feeding my kitties four or five different types of food for each meal. I thought if I didn't do that they would not eat since they didn't like the first thing I put out. I finally decided it had to stop and now they get two choices - one that Sam likes and one that Atticus likes. That's it. If they don't like it they can wait until the next meal time. Every time though, even if they don't want it when I serve it, they will come eat in an hour or two after they are convinced that I'm not going to give them any other choices.
There are also places where you can find community that don't cost anything - community centers, churches/places of worship, volunteering, walking clubs, meetups. It's scary to try to reach out and build relationships, but there are so very many people these days who feel exactly like you - and would be so glad to meet you.
I did this myself the first few months of this past year - I was so worried about taking care of Sam that I had really stopped going out with friends, and as you said, people stopped calling. I started to realize that no one knew I was sitting here wishing they would call. They were all thinking that I wasn't interested in spending time with them! So over the past few months I've been making a consistent effort and it's really paid off! It does take time to build or rebuild relationships, but it will happen, and if you are doing well, it will be better for your kitties too!
Hopefully starting work soon will help too. It can be so good to have someplace we need to go at a scheduled time. It might help your kitties figure out how to eat on their own too since you'll have to leave for work and won't even have the option of staying with them for hours to get them to eat.
Sending you hugs and vines of comfort tonight.
Oh, and if you're worried about Jester needing to eat before his shot - put out a food that he has eaten before and you know he doesn't hate. If he doesn't want it, give him a couple of treats - if he eats treats eagerly, then you know he isn't refusing food, he's just being stubborn. Give him his shot and just leave him with the food. You are monitoring him, so he'll either start eating, or you'll know he's dropping and can start fussing with his food at that point.