Serving God with your Profession

This month is the mission's month in my church...and last Sunday the message was very appealing and rather inspiring. A missionary in Cambodia came to preach and he talked about "Serving God with your Profession".
To cut the story short, this missionary guy is a dentist and he can earn good money and live a relaxing and rather peaceful life in Malaysia, but rather he chose to be a missionary to Cambodia where it's a rather dangerous and you-risk-your-life there. He served God there as a lecturer in the University by training up dental students and evangelise to the people there. (Serving with his profession). The point is, he said that he used to think..."I can help people by earning more money and donating to them..."....or something I forgot but it's something like that. Then he added (roughly remembered), "You really need to leave the field and go into these places and serve". But of course God would have prepared us to serve him in every different way..either overseas or locally.
I was rather inspired by him...since now I'm doing pharmacy...I think it would be good for me to serve God with my profession...and I wished to do so too! I remember seeing some lady selling crackers at restaurants...but I didn't bought any from her...partly because I don't eat those snacks and...I'm not earning any money yet...I don't think I personally have the right to be....you know..pay for these even out of my compassion. That's why I'm quite determined....to do well..and to be a competent and compassionate pharmacist! Hope I can survive in the final exams that is about to come..I guess I really need to work very hard..then come out to be a qualified pharmacists..and serve God by my profession..this is my resolve!
Though, life is really short...I don't want to be studying for my whole life!