Agree to take on some HTML training whenever your boss sets it up. Agree to attend training, but since you're an hourly worker, rather than a salaried employee, only on company time. You're not about to be taken advantage of. Make several calls about different training options, pick out ones you like best, and discuss them with your boss before getting the training set up. You're short about three courses on your degree, but things are so busy you haven't had time to think about registering this semester at the local college, where you've been enrolled part-time.
Today is the last day to sign up.
Just let it go - the diploma doesn't have much relevance to the kind of work you're doing now anyway and you'll make yourself crazy trying to do it all. Life's too short. Talk to your boss about finishing your degree - explain that you may be a little overloaded, but you feel you'll be a better employee in the long run if you take one course for each of the next three semesters. Start back at uni or college but don't tell anyone - they may take you less seriously if they think you'll get your degree and leave. It's important to you to do a good job and get things in on time.