After upgrade admin menu not coming
Can't tell you why, but can tell you how I fixed it last time when it happened to me:


Disable Admin Menu
Uninstall it if possible
Delete it's files and directory
Download and unpack fresh copy
Clear all caches (Drupal and browser)
Enable Admin menu


Worked for me, when menu disappeared during 6.x -> 6.x upgrade, when everything else failed to bring it back.

If the problem is only with core toolbar module, and not Admin Menu module, you have 2 options, really:


Try steps above, just for Toolbar. You can download core archive and then just extract toolbar's directory. Admin menu and toolbar are build in similar fashion, and purging all module's data is a pretty solid method anyway, so it still can work.
Give up on toolbar, and use 3rd party module instead.