Worried about Heartbleed? xkcd explains it in a way that most folks should be able to understand. It's pretty important to be aware of Heartbleed, because there is a decent chance you have been affected by it.
To see if a site you use regularly was hit, visit this site and enter your URL. Lastpass is a password management system, I use Keepass, personally, but if you want to be safe online, you should definitely be using a password management system. No one can possibly remember the types of passwords that are actually secure. Or remember a different password for every single site you regularly use.