Unhealthy relationship with food and weight

I am 17 years old. almost 5’6”, and about 155 lbs, which I know is a little on the heavy side. I am pretty dissatisfied with the way I look and my weight, but my main problem is I think that I am developing a very unhealthy relationship with food.

It started off with me wanting to eat better and exercise more to just feel and look healthier, but somewhere along the way it developed into something else. I’ve started over exercising and feeling very guilty about what I eat. If I don’t exercise I feel like I am not allowed to eat, but when I do eat I feel very guilty and like I should’ve, and could’ve, eaten less. If I allow myself to eat something that isn’t very healthy, but that I enjoy and should make me happy, I begin to feel very guilty about eating it. Every time I look in the mirror I feel like I am so fat and I think that if I was just skinnier all my problems would go away.

I just want to be able to have a healthy, balanced diet and be able to enjoy eating again. Has anyone else experienced something like this, or does anyone have any advice on how to get back to having a healthy relationship with food and my body?