Email issues with subscriptions. Please help

Provided I have just signed up here this week, I have other websites I am forumned with, and the options are the exact same.

Subscription

Subscribe to this thread and notify me of changes: Instantly Using Email

I always check the box also. For some reason though, the posts that I have created are not alerting me via email every time a member leaves a thread. I logged on today and yesterday, and saw many answers to one of my posts, BUT NOT EMAIL LETTING ME KNOW. I know my email is also correct because I received the activation email when I first signed up. PLEASE HELP