Any changes you make like taking vitamins will take about 6 months to see results on.
As you know stress makes the loss or thining worse.
I don't have thinning hair, but do have very thin fine hair to begin with, and it always bothered me when I was younger. The older I get now the more I wish it were socially acceptable to just shave my head.
I have a dear friend that has seriously thinning hair and she fights and struggles with it, and nothing really seems to make a difference. She isn't ready to give up the fight just yet, but suspect that she will be confident enough to just wear a hat or head scarf on most days as it progresses.
For some people this is genetic. I had a great aunt who was totally bald by the time she was 60. Her sister was a hairdresser and more hair than a poodle. LOL. She was a character, and she wigs in every color, and cut you could imagine. She had fun with it, and each day she was a different color and cut. She wore her hair like an accessory. I would choose this path myself if it does thin even more, and I develop a bald patch.