Calm down, remember you've gotten through this before you'll get through it now.
Propranolol and cocaine should not mix, ever, because cocaine increases your heart rate while propranolol disallows it to increase. They interact. But since the cocaine is out of your system you should be fine. Just drink a lot of water.
Propranolol and alcohol will dehydrate you so again, drink water.
You're not losing your mind. No matter how bad it feels, anxiety alone cannot cause you to go crazy. Meditate a few times today, just five or ten minutes at a time. You'll be just fine.