New guy setting up a CB/ antenna question

[Logan123]

Hey guys -

I'm new to the CB world and have a question.
I have a Uniden CB mounted in my truck with dual Firestick KW antennas on the bed of my F150. When I check the cb with the SWR meter it shows all maxed out readings every time I key the mic. I did some research and I'm thinking the issue may be with my antennas. I did not mount them using the mounting brackets that they came with. I just drilled a hole threw the bed of the truck (behind the back window) and tightened them there. See attached pic.

Should I have used the mounts? Could this be an issue with not grounding the antennas properly?

Thanks in advance for any help.
Logan