Lalania -

My aunt is nearly fifty and is single with no children. I think she was quite depressed about this for some time, until my mother suggest she consider focusing her energies on their aging parents. So, now she cares for them and has found a sort of purpose and meaning in that.

Not that you have to do anything like that, but I think it's about finding something to fill that void. Being single is actually quite liberating in the sense that you don't have to plan your life around anyone else. You can travel, you can move, you can make a drastic career change without having to consult anyone. Enjoy it! And if you still feel something is missing, there is no limits on how to let people into your life.