How on earth do you get your child to eat?!

My baby just turned one on the thirteenth. He's been breastfed since birth. Has refused any type of bottle or formula like it's a plague. Hates baby purees. I can no longer BF due to a new medication. But this kid won't eat or drink anything! I don't know how to make sure he stays hydrates and well fed! I try to feed him EVERYTHING! All he will eat is junk (toast, rice, pastas, fish sticks). Everything I feed him is whole wheat organic etc but it's still junk. He doesn't drink much water and hates milk. My doctor advised high fat foods so that's all well and fine but still he barely eats any of that!