How does one...

....check his/her posts from the topics they posted in?

Because really, I've been on forums in which you could check the latest posts, as well as new posts on topics that YOU posted on.

Is there such a way to check up on stuff like that?

You could search in ur username... The third tab after Active topics and Members list on top of the page

Yes, use the Search option. 😊

Yep use the search button..