Poor Peach Wookiee
! If it's a comfort: I have the same problem. Must be this crazy weather.
, the problem you describe sounds very much like a loose contact. If you're a good DIYer, you could open the oven and look where it is. Possibly near the door.
Do you only have a microwave or do you have a stove as well? In other words: are you going to have to live on cold meals the next weeks or do you have an alternative means of preparing hot food? (If the weather 's fine, you could BBQ