I don't get notified, what do I do?

Brittany ♤ • Muscle car driving mum to a beautiful rainbow boy who's about to be 2 and wife to a sarcastic Yorkshire Englishman. All hoping for another rainbow addition to our family very soon ♤

I don't get notified when people respond to a comment I have made, usually on a topic that I have created....

I have to go back and check..and sure enough people are responding or commenting new threads.

How to I turn this option on?