Selfless or Selfish?

Being selfless is such a difficult thing to achieve most of the time. You try to suppress all your feelings and doubts and troubles so you that you don't make others worry and weary more than they already are. But, sometimes I wonder, how long can one hold and suppress themselves and plaster on a smile before they break down and fall apart like everyone else?

Does being selfish and wanting someone else to be selfless instead a selfish thing to wish for? Or worse, what if you find out that deep down, the reason why they are so weary is because of you yourself? What if you were the cause of it and everything would be better if you just disappeared?

Is it ever possible to be selfless and selfish at the same time?