how do i find my topics i have posted on if i want to find them a day later or something? i dont see a search button for it.

You can find all your posts and threads you've created by going to your profile (click on the profile button located in the bottom left hand corner of any of your post or on your username at very top of the page in the upper right hand corner) then clicking on the statistics button which show you two links that say "Find all Post" and "Find all Threads"

Edit:
Oh you can also subscribe to threads. Whenever there is a new post in any thread that you subscribed in they will appear under the My Account Tab. To subscribe to threads, first check that the option is turned on. This is under My Account -> Edit Options -> Scroll down to Default Thread Subscription Mode. You can change the mode from there (you can get emails notifications as well). After that, the easiest way to subscribe to a thread is post in it.