Propranolol and effectiveness

Anyone else on propranolol? I'm using it to regulate my high heart rate and calm my POTS episodes which were causing syncope, nausea, shaking, dizziness etc. I take 10mg as needed throughout the day, which usually totals to about 3 doses. It works, but I still feel off. How long did it take for the medicine to take full effect and make you feel "normal" again after starting?