The thing that worked for me was something I learned from a book called "Babywise". It is all about the importance of a schedule and knowing what your baby's needs are. The key is that your baby has three times: Sleep time, eat time, and wake time. The important thing is to put the times in the right order. Sleep time is first, eat time is next, then wake time (or play time). Then, it starts over again. The older the baby is, the longer the play time is. If you always do these things in order, you will know when your baby is crying because of hunger or because he's tired. If he is crying during wake time, it will be because he's tired - not hungry because you already fed him. Also, this assures that you are not using food to put the baby to sleep which is sometimes easier, but often causes your baby not to get a full meal because he falls asleep before he is completely full which will make him not sleep as long and wake up hungry. The hard part is getting started and breaking him of eating whenever..but it is worth it!!! You may have to let him cry it out the first few nights that you are not "feeding him to sleep". Just be patient - it will pay off, and it will allow you to go back to work knowing that a caretaker is able to know what your child needs when you can give them a solid schedule. I also suggest introducing a bottle now too, even if it's breastmilk, so that he is used to it before you hand him off to someone else to feed for a day.
Good luck! Do you have family that can help you out with a car or with childcare till you get back on your feet?