Help!

I am usually pretty good at technological stuff and figuring things out, but I am at a loss - I don't know why my blog won't show it's updates on other peoples' blog roll. It has my most recent posting as one from last May. I know I've been slacking, but I have posted since then. Do I need to do something with the site feed or with Feed Burner? The updates show in Google Reader, but not on my follower's sites. Its driving me nuts! Help a sister out, please!