No worries rod we can get this fixed, I’m starting to suspect you may have some kind of infection on your Mac.
You should really consider reinstalling your operating system if it’s within a year old you should take it to the genius bar if it’s within 3 years old and you have Apple care they will take care of you as well if you.
Lastly you may want to consider getkimshelp.com
If you are able to make a backup of your computer, Using time machine and an external backup hard drive via USB. it should cost no more than one hour’s labor if you have to take it into a local computer shop to get your operating system reinstalled.
Or you can even attempt it yourself by following the link here.
Best of luck.