iCloud deleted contacts from 4s

I have managed to lose all of my contacts from my 4s whilst setting up my old 3gs for my girlfriend, I inserted her sim and my contacts were still there, I began to delete my contacts from this phone, it was after I had done this I noticed that all of my contacts that were on my 4s had been deleted and replaced with her contacts. It now appers that her contacts are in the cloud as my original contacts have just been replaced on my iPad with her contacts. Is there any way of retrieving my contacts?