They say 'I feel like I have no friends!'

That word 'feel' again. I know where they are at though. We are often all guilty of 'imagineering' situations. Some also call it 'awfulising'. It really means losing or creating a false perception. This can happen when we are tired and depressed. Often results in worrying. I found this helpful(don't know the source though)
Of 100% of worries
40% Simply never happened
30% Past events - totally out of our control
12% Your health - or a 'dis-eased' imagination
10% Family qualms that are groundless
8% Worries that have a basis in conditions that can be treated.

Yourself can always be your first 'friend' !However, it is also possible to be that focused that we don't appear to need friends.

It is intersesting to examine what evidence we use to create our perceptions.There is a tension between our self-image and the image others have of us. Which do we use as our point of reaction.How many friends are required to overcome 'loneliness' ? Do we often seek company because we don't like being alone with ourselves(Does this mean we need to value ourselves more !)Does it also mean that when we meet people we demand 'positive' feedback ?

Friends often exist for 'seasons'. Some stay around, some leave, and others arrive. That doesn't mean that you are the reason for it.