I'm still fat a year after giving birth. Help!

I've always been skinny with a flat stomach and after giving birth all that changed. I tried not to care so much because everyone said it will go back, but now it's been too long! I've been breastfeeding the whole time and was back at my pre pregnancy weight already a week post partum. I've been taking at least two two hour long fast pace walks every single day since giving birth. I weigh 48 kg (normal for me as I'm short) but I still look like shit and I'm fat and I look pregnant even though I'm not because I haven't had sex since I got pregnant because my baby's dad left me . I can't wear my normal clothes still because I look so pregnant in everything. My body is embarrassing and frustrating and I've never been insecure about it before . I would have worked out more, but I'm alone with my baby and baby wants to be held too much for me to be able to work out. I'm sometimes thinking about going to a doctor because this is insane. I eat healthy and regulary so I don't think that's the problem. I need help and advice. I'm devastated.