Playback setting options under RT button are missing?

I lost the ability to change the playback settings via the button on the left of the timeline. I cannot view my edit in real time, it drags, drops frames, impossible to sync audio, etc.

I could be wrong - but I thought I used to be able to click the button that says "RT" - under which I would have multiple quality options I could check or uncheck to make the edit play more smoothly. However, now the only options are "Play Base Layer Only" - which is checked - and two "Record to Tape" options. Did I accidentally change some preferences at some point? Seems there are multiple options missing under this button.

Any tips greatly appreciated!

-E