I'm Having Trouble Eating. In The Beginning I Fine Then

I'm having trouble eating. In the beginning I fine then I start eating very slowly and I get all tense and have a feeling of choking. I take a long time to eat and I swallow very small bits of food at a time while I chew. I feel like I forgotten how to swallow my food properly. Please help me. I'm only 15 and I play sports. I'm skinny and I really want this problem to go away. Please and thank you