cannot save the newest version into the local history

I've noticed that when I commit changes to github it seems that these changes do not automatically become the most recent file in the local history.  Also when I use 'put label', it is also not the case that the latest version will be reflected in the local history.  So what happens is I commit my changes, called this newest version, then I revert

to an old version of the file, I look for my mistake, then I revert back to the newest version but it will not revert back to the newest version but to the newest version minus a few changes.  I then have to put these changes back into the newest version.  How do I prevent this?