Welcome, Sprite22!
Don't worry about missing any thread you start (or, in fact, any that you've posted in). Just click on "My Profile" (near top of page, on left) and it will take you, well, no surprise here, to your profile(!) That obvious bit brings you to what might not be obvious. Part of your profile there are your subscribed threads (any you start or post in is automatically included. You can also choose to follow a thread by using the "thread tools" button when you are on a thread. (If those first two aren't automatic, let me know. I might be forgetting a setting or something. It's been awhile.)

When you're looking at your subscribed threads list, it will have a little arrow to the far left of the thread title, which works just like anywhere else on the site in taking you to the posts that are new in it since the last time you were reading it.

Enjoy!