Hello and welcome to the forum.
I have Windows 8.1 Professional and the free Windows 10 only installed Windows 10 Home Edition
How did you perform the upgrade?
Did you use
http://www.microsoft.com/en-us/software-download/windows10
AND perform an upgrade in place in real time?
OR
Did you choose to create media for installation later?
Typically the in place real time upgrade will provide a like for like in version and bit architecture upgrade.
I would say the first thing you need to do at this point is secure your critical data by performing a backup as well as a system disk image.
Read this....
https://www.windows10forums.com/threads/please-for-your-own-peace-of-mind.794/
Then you will likely have to roll back your current installation to your former version of Windows 8.1 Pro.
Confirm that everything reverted successfully and that your former OS is intact and updated fully and is activated as "genuine".
After which you can attempt another upgrade and you may want to secure the correct version and bit architecture ISO using an alternate resource.
https://www.microsoft.com/en-us/software-download/techbench
Good luck and keep us posted.