OB nurse working Med/Surg

I have been a nurse for 5 1/2 years, I spent the 1st 6 months out of school working Med/Surg and then transfered to OB. I love OB but census has been low so I offered to pick up extra shifts on the Med/Surg floor. I was very up front with Med/Surg management and let them know that I am very comfortable with surgical pts and not comfortable with medical pts and that I would need help with things like peg tube management or chest tubes and such just because it has been years. I was assured that I would mainly have surgical pts and would have a charge nurse to help with anything that was unfamilliar. So far that has not been the case. The last day I worked Med/Surg I had 3 pts on isolation that were also total care and one had a peg tube and feeding to manage. No one was available to help. My other 2 pts were pretty straight forward thankfully. Can anyone suggest any resources that would be helpfull? Is there a certain way that I should ask others for help? When I asked the charge nurse for help she asked if it was hard to work for a change, I replied by stating that I could tell that she was too busy to help and that I would find someone else. I'm sure that for a seasoned Med/Surg nurse this more likely than not sounds like a cakewalk but I haven't done this in a long time. I really want to do a good job and give my pts the care that they deserve. Any replies are greatly appreciated, Thanks.