You should still have access to the export features in Lightroom CC. Using the export dialogue, you can export all of your images. Then you can import them into your Lightroom 5 catalog.
No there is no way to open the CC catalog in Lightroom 5.
But if you can still access Lightroom CC then you can export your images from CC catalog, If you do not want to loose the work done so far.
That would be the edited copy if you have made any adjustment to them in Lightroom.
Select all your images. Then use CmdS (Mac) or CtrlS (Win) to save metadata back to the files. You can then create a new Lr5 catalogue and import the files. So no exporting. You'll lose some things (stacks, collections, flags, brush adjustments to radial and grad filters) but will have most of your work.
Alternatively, just buy the Lr6 perpetual upgrade.