Premiere Pro is not exporting what I see in the sequence I have edited

Beyond Ann's response you may also want to look at using Software Encoding if you're going straight to H264, rather than Hardware Encoding. You can also try exporting to a different video codec altogether like Quicktime ProRes 422.  

Hardware Encoding tends to be a bit more error-prone, especially with sequences with more complex editing, VFX, etc. I personally only use it for review versions. The speed is nice, but I usually want to end with something more reliable. Exporting to a HQ Master like the ProRes I mentioned is also a common move for exporting, again especially if it's a more complex sequence. 

You want Ann to explain how the whole program works in response to this question? Clearing media cache is a valid first step for this issue, and asking to see some more specific information is a good next step. This comment seems very out of place so maybe it was meant to be in response to something else?

Start with clearing media cache and preview files

FAQ: How to clear media cache files 

Post screenshot export settings with left tab to output with an image (not black).