Sally, for most of my life I have been anxiety free. I did deal with depression in my earlier years but meds helped a lot.
This winter, I started feeling bouts of vulnerability and anxiety. Like you described it would last through the day and even to my free
time and weekends. I do think this is GAD, generalized anxiety disorder.
To fight it, I've started a regime that's helping:
In the morning before work, I sit in front of my light box for 30-40 minutes.
I do buddhist chanting and some physical x (jumping jacks and running in place).
I also am helped by these affirmations: "There's nothing to be afraid of. Nothing will come up that
I can't handle. Have an amazing day." If those affirmations don't work for you, you can find others.
Hope that helps. Hang in there. Never give up fighting for your happiness.