When I flare, here are some of the things I do.
First of all I cry. A lot. Then I call my doctor and cry to him. Have him schedule tests, appointments, put me on steroids, whatever needs to be done. First priority is definitely to get the flare under control.
Rest, rest, rest. It's incredibly exhausting being in a flare and you need all the rest and sleep you can get. Don't worry even if your house gets messy, that can wait (I say this as someone who just vacuumed her house for the first time in over a month).
Distractions are good. In this current flare, I've done a LOT of crocheting (I finished an entire blanket in 5 days which is a new record for me). I also played with Legos a lot. Yes, I'm an adult. But I found it was a really nice distraction to get a new Lego set, follow the instructions, put it together. It's fun and kept my mind off of how icky I was feeling, and I could do it from the couch.
As for food, it was not my friend at all in this flare and I had to do an elemental diet for a couple weeks. Now I'm doing low-FODMAP and starting to feel well again. If food isn't going so well, try just having liquids like broth or Ensure for a couple days. Then move on to very bland foods like plain rice.
Do something nice for yourself. Prednisone has made my skin not so pretty, so I got some fancy face masques and have been pampering myself a little bit. That has made me feel better mentally, like I'm worth pampering.
Oh, and online shopping is your friend. Some days I could barely drag myself to the couch, there was no way I was going to make it to a store. I got my legos and face masques online, so much easier than physically leaving the house.
Having said that, exercise as much as you are able. Even if that means just walking from one end of your house to the other. Walking is important and good for the gut. Don't overdo it, listen to your body and do not push yourself. But do try to walk as much as you are able.