I have created another thread which explains in more detail my lost menues:
But to make long story short, I can log in to the CRM (both as admin or as regular user), login screen appears to be intact and works correctly. It is just that when I log in all of my navigation is gone (literally all) and if I manually go to (for example) suitecrm/#/Contacts and I choose a contact from the list, it will open my contact card and will show recorded data but all of the lables will be missing.