NEED HELP W SELF CONFIDENCE

Ca
So I'm 18 years old and have always struggled with self confidence. Since the 6 grade I was bullied and called ugly and a crazy horse girl ( I ride and train horses and they've always been my passion) and was a late bloomer. I'm not curvy and I'm not skinny. I feel like a weird shape caught in between. I used to be a very successful track and volleyball athlete as well but have since lost my drive and motivation to work out. I have a job and my boyfriend plays football so I try to spend all my free time with him. My mother constantly has been telling me that I need to fix my body. That " she can see my cellulite through my legging" or "such in your stomach" " you look 6 months pregnant" " you used to be so fit" no one knows I've had underlying self esteem issues and lately it's been really bad. My boyfriend is kind and says he loves my body no matter what but he wishes I would be healthy again. I guess I just feel really bad all around about myself. Any suggestions to get my drive to work out back or boost my self esteem. Thank you ladies.