A lot of good advice here (exercise/social contact/diet/sleep/CBT), but here's my primary suggestion:
Take small steps toward self care, and realize you won't feel like doing any of them beforehand (even though you'll feel better for having done them). For example, cook for yourself. Clean one room in your house. Mow the lawn. Shave. Take one piece of trash out of your car. Say hi to a neighbor. Do one set of pushups.
Give yourself permission not to get better all at once.
Take small steps toward self care, and realize you won't feel like doing any of them beforehand (even though you'll feel better for having done them). For example, cook for yourself. Clean one room in your house. Mow the lawn. Shave. Take one piece of trash out of your car. Say hi to a neighbor. Do one set of pushups.
Give yourself permission not to get better all at once.