Antibiotics make me feel better after 3 days but I feel its only 50%. What should I do if it doesn't heal completely. Chest infection. Supplies ending?

Unclear. What kind of a chest infection do you have? If you have a bacterial pneumonia 3 days of antibiotics, assuming they are appropriate, may not do the job effectively. Go back and see the physician who gave you the antibiotics and describe your symptoms and get reexamined.