Hi missygreta,
You would be better off starting a new thread in the Windows 10 or Windows 8 forums in order to get appropriate responses from forum members who have more expertise regarding Windows 10 and 8 than I have. However, I can make some points about your predicament.
Firstly you need to clarify your position - it seems your Windows 10 was an upgrade from Windows 8 but did you use the option to upgrade for free that Microsoft made available when Windows 10 was first introduced? Unfortunately, even if you did get Windows 10 this way, the included easy option to return to your original operating system will not be available as that had a 3 month time limit. Much now depends on whether or not you have installation disks for Windows 8 or if you have old system image file backups saved anywhere. It looks like you will need to undertake a full installation to achieve what you want and that needs careful planning if you are to avoid major problems. You need to consider Windows Updates, program installers, drivers and data files. The latter, which are now on your system, should be safely backed up on to an external device so that you can put them back after re-installation. All this may appear somewhat daunting and actually may not be necessary if you can fix the update problems in Windows 10 itself.
Windows 10 has a record of updating problems particularly for those who upgraded their systems from a previous operating system. Many of the problems are caused by updates stalling, not completing and corrupting system files. Such problems are not necessarily permanent and often can be fixed. If you explain the issues you are experiencing (with as many details as possible) in a post in the Windows 10 section, you may well find someone can provide you with information to enable you to cure the problems without the need to downgrade. Good luck.
