not getting emails from my site

[CatherinePooler]

I set up my site so that everytime someone posts anywhere, I get an e-mail.
Also, when a paid subscription goes through, I get an email for that as well.

A few days ago, that stopped and I'm not getting the emails.
I didn't change any thing and I've gone in to the cp to make sure it is still set up correctly under forums and in settings under User Registration Options, it is set to my email to notify when new members subscribe.

If anyone could shed light on what is going on, I would greatly appreciate it!
Thank you
Catherine