The more you perform at the stand up comedy open mics, the more you’ll get comfortable in a very uncomfortable circumstance. Performing at open mics is a phase you will need to go through.
When you get the light, trust it, even in the middle of a bit, end your show and get off stage. Stand Up Comedians who decide to ignore the light to finish a bit or keep searching for that last big laugh will go over time. Learn how to only do the amount of time you’ve been given. That’s being a professional.