You will look more toned directly after exercise, not just a trick of the eye. Especially with a long run like you did. The muscles contract and take a while to relax and stretch back out, gives the appearance of tighter, toned muscles. Blood also rushes to the muscles which creates a bit of a swell. That is what happens to me after I exercise, and like Sunny mentioned as well, dehydration can also be a factor. Dehydration will also cause your muscles to cramp up.

The rest of it I can relate with. I have bdd along with anorexia. What is more concerning to me is about how you feel about food and your body. Cleaner, coating of grossness, feeling like you have instantly gained after a meal and feeling disgusting, could all be troubling feelings when relating to your body and nourishment. So that is not to say you are not suffering from bdd or disordered eating, or unhealthy food and body realations. Because it seems to be effecting you. I

A burger may feel gross, well it is greasy etc. Healthy food naturally does feel better especially if you are exercising alot. The body will likely crave healthier more nutritious food then. This thought should probably not go alot further to where you are labeling your body as disgusting. Maybe a burger is a bit fatty, make you instantly fatter ? No, that is where I see some potential trouble.

You seem concerned, and do have concerning feelings. I think that warrants talking to a professional about it, and getting feedback and help for issues you may have here. Worse thing would be to ignore red flags and end up with a full blown ed that is out of control right?