I didn't know why I wasn't getting notifications from threads I had participated in, but thanks to moderator Janice I know what to do, thought I'd share it.
You need to individually subscribe to each topic.
"It is not automatic to have email notification of each topic where you post. You must choose to add it. Every time you are in a topic, you can add that topic to your Watch List. Go to Topic Options > Add Topic to your watched topics."
Oh, and I just noticed under this window I'm typing in a check box "Add this topic to my Watched Topics". I'll check it and see if that works.