New RN: charge RN for noc, and freaking

Hi, everyone. I graduated in May, and was hired for my current job in August. I got 1 month of orientation, and then I've been on noc shift as the only RN (1 LPN and 1 aide working with me) as charge. I'm so stressed that I feel like I could cry and/or have a panic attack before my shifts. I've been doing fine, but my last shift was horrible: I was the only person from my facility, and had 2 people float in to help me from our associated Hospital. (We're a separate building.) Since they weren't familiar with things, I kinda ended up doing 3 jobs that shift and felt like I was going to drop over w/ a heart attack I was so stressed. I mean, they were wonderful to come and float over and help to the best of their ability--they were super sweet and helped out as much as they could, but what I do (chemical dependancy detox) is waaaaay different from their department (birth center.) We're so short-staffed at our facility, that I know this will happen again soon. I'm trying to psych myself up to go into work again.