Hi OR, welcome...and Happy Birthday!!
Thank you for introducing yourself and giving us a good deal of background. Sharing your story is very helpful.:)
I am sorry to hear of your mom's illness and passing. It is easy to see how this can be an anxiety trigger. You are not alone in this, and many people have increased/returning anxiety due to similar circumstances.
In answer to your question, the reason that A/D's are used in treating anxiety as well as depression is two-fold. One reason is that they often co-exist...but beyond that, it is simply because they work on the neurotransmitters in the brain in a similar way.
An SSRI for example is going to work on Seratonin, while other meds work on Dopamine...(nutshell explanation!) these chemicals affect both depression and anxiety, and leveling them in the brain is going to have similar postive effects in terms of both depression and anxiety.
On the other hand, a benzodiazepine, which is considered an anxiety med is just that...an anti-anxiety med.
Doctors usually prefer to prescribe an A/D (or combination of A/D and benzo) over a just a benzo alone...as the latter can pose a dependency risk.
(there are other considerations besides SSRI's and benzodiazepines in treating anxiety medically. Off label use of Vistaril/antihistamines for example is something you can discuss with your doctor...as well as other meds such as Buspar/anxiolyctics)
Have you considered returning to using self-help, or the treatment option of therapy?
I found great benefit from both.:) CBT in particular was amazing in treating my panic issues, health anxiety and physical symptoms.
We have great material in our Resources. See our main page, 1st post for infor and self help recommendations.
Keep posting with us as well. Support is key, and we care and understand!
Talk to you soon,
Scaredy Cat