[GeertB]

You probably work too many hours, and actually can more often say 'no' than you think. Delegate some of your responsibilities. Work smarter, not harder. Be transparent with your manager about your night classes and the need to change some schedules. If your manager is sensible, they'll take 80% of your known performance at our level of experience over uncertainty and a long ramp to reach the equivalent of your 80%. Sure, there is a chance they won't accept, but it might be a risk worth taking. Oh, and by going to school you surely show that you want to grow.