Body Image Issues

I have have hated my body since I was 16. I have managed to deal with it at different periods of my life and at other times it is crippling.
Over the last year I started competing in Body Building competitions and did very well. However since finishing up the season and coming back to a healthy normal weight I have struggled with my body, size and shape. I hate seeing photos of myself and wont look at them. I am not overweight but would like to be smaller than I am and it consumes me to the point that I fail at trying to lose weight on a weekly basis. Then when I do “fail” I hate myself all over again!!
I am 54kgs and want to get to 51kgs but feel like it is impossible!!
I recently participated in an 8 week challenge and didn’t finish the challenge because I gave up. This in turn really affected my feelings about myself and I had so much shame around failing at the challenge that I spiralled out of control.
I dont know how to get my brain to the right space to lose weight again and stop hating my body.