I graduated college, went away to teach English in another country for a year, and came back to the United States with a nice amount of student loans knocking at my door. I applied to all jobs across the board pertaining to my degree and no one replied. I decided to go into another realm: programming, which I had taught myself at a young age (12). I applied and managed to get the job. I had some training to do in order to catch up, but I was paid starting at $10/hr. After my training was complete, my pay was bumped up to $12/hr.
At that rate, you know how long a $40,000 student loan was going to pay off? I needed to do additional work to catch up. Basically, I designed and developed Auto-Collision software, from adding new things to mostly fixing up old bugs & errors, etc. Severely underpaid. I loved the job but my boss made my time there hell. He was a micromanager. He taught me a bit of logic, but really didn't do me any favors.
During my time there, after work, I'd go home and search Craigslist for people looking for web designers and managed to make some good money that way. About a year and a half later, I had already gotten deep into web design and development, which I loved. It wasn't enough to quit my day job, but it was enough to give me the confidence to start looking for other jobs in that area.
To make a longer story short, I ended up leaving, but before I left, my boss had offered me double my salary. So I would've been making $24/hr. I turned it down because with that offer.. everything came with a catch. If I made any errors or anything like that, he would've thrown it up in my face: "What am I paying you this amount for?" etc. So I couldn't deal with it and ended up settling for less. More than what I was making, but far less than the double salary. I didn't care because I managed to accumulate a lot of experience within the next 5 years.
I ended up getting 2 web design jobs at the same time (one from 8 AM to 5 PM and another from 6 PM to 2 AM) and did that for 2 years before getting laid off by the former, and now I currently work the latter. About 2 years later, I would end up making the salary he offered me, plus benefits and a ton of vacation time and the freedom to not have a "micro-manager" constantly hovering over me.
You can read more about it here: http://confessionsoftheprofessions.com/the-opportunity
Anyways, the point is: Sometimes you do have to stick it out for a time, but take it all as a learning experience until you can quit the job and get one you love. If you aren't happy doing something, than find something that makes you happy. It makes your life totally worth living.
I not only still work at my day job, but I run a freelance business, a software company, and several side projects, and although I find myself working 15+ hour days sometimes, I love it and I don't think I'd have it any other way. If you take everything you learned and you apply it, you can make an excellent living, but turn that living into something you want to be doing everyday.
Also: The more you know, the more valuable you are. If you've gone 6 months to a year and the company has grown and yet you've seen no "returns on your investment", than start looking for another job, but don't be afraid to ask them to consider "better benefits" for you or at least a raise.