I get this all the time. Sometimes it gets overwhelmingly severe. I try magnesium first. Then I do a shot of methylcobalamin B12. That usually helps significantly. In fact, I would have had to go completely off all treatment due to horrible anxiety herxing if I hadn't started B12 shots. They help depression significantly as well for me.
If I still have anxiety and I need to go to sleep, I take ashwagandha (an herb that helps your body deal with stress), Valerian root, or benadryl 50mg.