Your grandma did not screw you over. She might have been concerned that you were eating too little.

And I'm with everyone else -- that 4lbs is most likely water weight.

Here: There are 3,500 calories in 1lb of fat. In order to gain 4lbs of fat between Friday and Monday, you'd have to have eaten 14,000 calories. I very, very seriously doubt that happened.

I think your grandma just wants to make sure you're eating enough because she cares about you and your health.

You need to take responsibility for how much you eat. No one else takes that responsibility for you. You said you ate too much, but how can you eat too much if you're not hungry?

And why do you believe you won't lose that 4lbs?

I think you're projecting all your negative feelings and shame against yourself onto her. You feel like you screwed yourself over. You feel like you should be ashamed of yourself.

You need to be much, much kinder to both yourself and to her.