Really it is a matter of breathing. They say holding you breath & then breathing out slowly. It's a matter of being in control. What about listening to music while you go down to them. I think if you love these piggies you have to get a grip. I don't mean this in a nasty way. The other thing they say is good is yoga, that teaches you to relax in all areas of life. Good luck.
Perhaps having a favourite picture or even better a video of your piggies might put you at ease? I'm currently on holiday (wifi not too good! So excuse any double posts or errors LOL) and I am worrying about my two baby boys. I feel stupid becuase this isn't even the first time leaving them- though it is only Steve's second time of being somewhere else. Naturally I have a little nagging feeling cutting away at me wondering what they are doing and if they are ok- so when I get really anxious I like to watch a video of them popcorning about or a picture of the two together.