Treat yourself well. I buy myself flowers every week. I like seeing them every day. Think of something that you can do for yourself every week or every day that will give you the same kind of joy. Avoid people who annoy, harass, or bring you down.
Life is too short to waste on irritation.
Toxic people around you hurt you. Check in with yourself often. Think of yourself first. You'll be a lot more help to everyone if you are not killing yourself doing things that are someone else's responsibility. Don't feel guilty saying no.