My contacts keep dissapearing on my iPhone

Last night I went to my texts on iPhone and half had returned to just numbers ,no name. So I went to my contacts and found that these contacts were missing. So I spent time entering them all again.. I got up this morning and went to my phone and found the same had happened again. I looked at my iPad and contacts were still there so I turned Internet on thinking that Icloud would update my phone for me but instead it deleted the same contacts from my iPad that were missing off my phone. Help. What's going on? It deleted some others that hadn't sent me texts as well and I've lost those numbers completely. Any ideas anyone??