Your Computer is low on memory.

Thanks for posting the screenshot.

1. The first problem I see is the process "antivirus." Do you have any antiviruses installed on your mac?
2. The popup asking to control safari is probably coming from an unwanted application or malware. I recommend that you do not grant it access.
3. Download Malwarebytes from https://malwarebytes.com It is a free and safe app that you can use to scan your mac for malware. Please run a scan with it and post the report here.
4. I can also see that MacKeeper is installed. MacKeeper is a scam and should never be used. Malwarebytes will help you remove it.

Please reply as soon as possible.

Try this:

Move your mouse to the bottom of the screen (where your apps are) and click the rocket icon. Next, search for "activity monitor." This is a built-in app that shows you what processes your mac is running (similarly to task manager on windows.) Open the app and click "memory." Is there anything using a significant amount of memory? It would help if you posted a screenshot here.

The message about memory being low can also be caused by malware or unwanted applications (This isn't necessarily the cause though). Visit https://www.malwarebytes.com/. Then, download the free malware scanner and make sure your mac doesn't have malware. Malwarebytes is safe to use and is frequently recommended by users on this forum.