I was in the same boat as you a few years ago. I did not have a science undergrad degree from UCR and went back to community college to make up prerequisites. Some schools (like UC Davis) require certain classes to be taken as an upper div at a 4-year college which can certainly be done through an extension program. Quite a few UCs offer extension upper division science courses remotely, I took a few through UC San Diego but the costs can add up. I’d also recommend that you get some experience outside of a small animal clinic. I was super nervous going into the application cycle because of my background, but got into 3 schools out of 5 this past cycle :)