Anxiety disorders and cannabis are not a good mix. Seriously.
I can't do a copy/paste ATM, but you'll find something I wrote on the subject over a decade ago here
. I haven't looked at the research on this for a year or two, but I'd be surprised if there have been much change in the understanding of how cannabis interacts with anxiety since then.
I particularly draw your attention to what I wrote about shrinkage of the hippocampus. What wasn't known back then is how crucial hippocampal atrophy is to anxiety and depression, or that antidepressants work because they reverse the cell loss in this area of the brain. Your cannabis use is actually counteracting what Zoloft is doing which may explain why you are at the highest recommended dose.