If you are suffering badly go back to see your doctor as he/she may be able to give you something else instead of propranolol. It gave me terrible headaches to start with but they did become more tolerable after a few weeks. I also felt a little sick too but not as bad as youre feeling. the heat intolerance will pass as your levels return to normal, unless like me you're going through the menopause, in which case it continues (sigh).
Hopefully you will start feeling better soon.