Weight gain

Hi girls so I had my baby boy nearly 5 months ago. He's my first baby, through the pregnancy I obviously gained weight. I was on the skinny side before I fell pregnant, weighed 7stone something, I thought that I would of weighed more after the baby but ive been loosing weight. I'm always eating and I'm just not putting it on, I feel uncomfortable in my self, don't like the way I like anymore and people are noticing that I'm loosing weight. I've tried shakes to help me gain weight back on but there not doing anything. struggle with anxiety but I know I need to go as it's getting me down. Does anyone know what the doctors could offer me? And what do I say to get an appointment about my weight? 

thankyou Xx