Ok as most of you know steam has had issues today and a large number have found that all their friends were missing.
I was in this boat and decided not to accept any new friends requests incase it messed anything up when steam tried to fix the situation.
What I also did ( which I dont know for sure if it helped ) was post my steam community info in this link.....
Missing Friends In Friends List - Discussion Thread *Fix Coming Soon!* - Steam Users' Forums
which a valve member posted saying they were working on a fix and if anyone wanted their friends looked into to post their account name or community link in that thread and they would sort it out.
Hope everyones issues work out soon