What you need to understand is that your mind likes to prove itself right
If you continue to tell yourself that you are disgusting then your mind will continue to find evidence to prove you right.
But if you tell yourself that you are loveable and worthwhile and good enough then it will find a way to prove this to you instead.
There is no objective truth. There is only the reality you create inside your mind.
When you remember a past event, you are actually remembering the last time you recalled it, not the event itself.
The research, conducted by Northwestern Medicine shows that recalling a memory more often makes that memory less accurate, and that every time you take a memory off the shelf in your brain, you put it back just a tiny bit different. Researchers conducted the study by having people relate objects to locations on a grid over the course of three days. (Full article)