@decemberriver - Welcome to Mayo Connect. I am glad that you found us! As you read the posts on this topic you will see that many many people have experienced exactly what you describe. Any of the new anti depressants are very tough to get off of. Effexor among many are serotonin-norepinephrine reuptake inhibitor.
https://www.mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/art-20044970
Taking the capsules apart is the last step that many on here are taking. Please read the posts. You will get a better idea of what to do. @jakedduck1 is one person in particular who has good advice about this.
When I took Effexor XR it was for menopause symptoms- depression and hot flashes. I also found that I had built up a tolerance for it. Let me know what you plan to do. Please check with your doctor and see what he has to say.