Is buying a house on one income a good idea?

My wife and I found a house we love and are trying to decide whether to buy now is a good idea. I recently returned to nursing school and has another two years , so now we are living on an income. She does work part time and make enough to cover your expenses (gas , telephone , insurance, etc. ..) . Currently own a condo that is rented by buying a house. Which currently take home around $ 3000/mos in net income and the mortgage on the house we are looking for would be around $ 1200/mos (this includes taxes and insurance) . The only other debt we have is my student loan , which is about $ 150/mos , otherwise you are debt free .

After buying the house would be about $ 20K left on our rainy day savings account. My concern is that if something happens and I lose my job over the next two years , we would be screwed. In this economy could 6mos a year to find another job, if not more. I've been with my company for a little less than a year and am in a rotation program with them. Basically, I turn to the new department every six months for me to learn the business for a period of two years. It is a very small company privately owned so there is no formal procedures for human resources. I feel a little unsure because I have a permanent position in the company yet and am not very visible to the leadership, while in the rotation schedule .

Is buying our dream home worth the risk , or is my only insecurity and paranoia we wait until my range is made with the school?