Why did my work load quadruple when my pay didn't?

I'm still at work and it's 11PM. I've been so busy these days. I have to now get on 7:30 AM conference calls(thankfully at home). But I also am not used to my early morning schedule so I'm more tired these days. I took a nap on the bean bag here at work and I'm waiting for the Moscow developers to get in the office. The CTO went over the project plan that I have to accomplish within 90 days with our outsourced resources in India. Right now I'm only overseeing one product (a large product, but nonetheless, just one). I now have to have a good grasp of 4-5 products. Even though I don't have to know it too much in detail; I'm overwhelmed that all of a sudden, my work-load has more than quadrupled. Even though I have deferred my management duties to the new director we just hired, I still have to train him, get him up to speed and participate in all the meetings and conference calls.

Lately I've been relying on this one guy who reports to me a lot to get things done. If it gets too crazy, I'm going to quit. I'm not one of those people that live for their jobs. I believe in balance and quality of life. And I lean more towards the leisurely lifestyle so too much work isn't something I want or good at handling. But I must say, I learned a lot at this job, and still learning. I now have some management skills under my belt as well as more technical skills. Also, a lot of my management kills are remote managing which is difficult in its own way. I also got better in presentation skills; I had to do a lot of product training lately because of all the new people that started. Now the ultimate test that will make or break me is multi-tasking on multiple projects. Contrary to popular belief, not all women are good at multi-tasking. I suck at it. I prefer focus on one thing at a time. I get REALLY overwhelmed when I have to do too many things. And I have a tendency to stress out. I don't really take things in stride. But being able to handle stress is like a muscle; you just have to slowly train yourself to develop those stress handling muscles. We'll see how long I last. I have no interest in seeing how far I can stretch.

Even my boss was like, "Can you handle it? I'll help you as much as I can." It should be a fun challenge though. I'll have to negotiate salary when it gets really tough.