Facebook problems

[JG1965]

I have private messaged some friends on Facebook a couple of times over the last two days now they have disappeared from my Friends List and I can't find them in Search, although when I signed into my account once today and typed in one friends name in the search it came up, so I tried another friends name but nothing showed up, so I typed in the first friends name again but this time only a matter of a few seconds later and there name did not show up this time, why did it show up then the next time it didn't?
I don't know if I have been blocked by them or not and I don't like to ask them, it just seems to be people I have private messaged, I wondered if my account had been hacked as I received an email a few days ago meant to be from Facebook saying that my account had been hacked and to change my password, but I thought it was a fake so did not bother to change my pass word.
Has anyone else had this problem?
Thanks in advance.

[ummmm]

If you block someone...then unblock someone...you can't block them again for 48hrs.

[ummmm]

You don't mean that!!!

[ummmm]

<blocked>

[ummmm]

<poke...don't like being ignored>