Thanks. I recommend creating a backup before doing anything else, in case something should go wrong with continued troubleshooting. To learn how to do that, please read Back up your Mac with Time Machine.
- A backup is a fundamental prerequisite regardless of whatever method you may choose uninstall adware, and would apply even if your Mac were running perfectly well. Do not overlook this fundamental requirement. It's important.
Then: completely uninstall whatever it was you installed in an effort to fix the problem, to include useless garbage such as "Adware Zap Browser Cleaner", "BitDefender" and any similarly categorized product you may have installed. Rule 1 of Macs is don't install junk.
Then: please determine if the same problems occur in "Safe Mode": Use safe mode to isolate issues with your Mac.
Additional instructions will be predicated on those initial steps.