It might be Telogen Effluvium - the hair can fall out for a whole matter of reasons, stress, sudden weight loss, illness, vitamin deficiencies.
I developed it last year having been ill for a while (non-COVID but possible cancer) & a very rapid weight loss - 30% of my weight. There was a lot of stress as I was having to deal with it alone due lockdowns etc.
Plus there had already been hair thinning as a result of the menopause, the gift that keeps giving
At the time nothing happened but a few months later & woomph! The hair loss started.
I saw a dermatologist/trichologist who diagnosed the TE & also mentioned I had psoriasis which wasn't helping.
I use Nizoral once a week & massage in coconut oil over night at times to ease the tightness of my scalp.
Once I'd recovered from the illness my diet went back to what it had been previously ie good nutrition. We did bloods & my levels had returned to normal.
I take a general vitamin for menopausal women, fish oils & collagen plus HRT. I try to eat lots of protein - full fat milk & eggs.
My hair is slowly returning. I was fortunate that I had a real mop of thick hair so the hair loss, whilst noticeable to me, doesn't look too bad to others - or so they tell me, bless 'em.
Keeping it short helps.
The hair is growing back grey & very fine. It tends to snap easily so I'm very careful about styling & have bought a silk-lined beanie as usual hats to make my hair break off..
The main reason I have about possibly getting COVID is that I don't want any more hair loss if Im really poorly. Vain or what?!?!
There are various support groups on Facebook - the Telogen Efflovium Support Group has been brilliant - lots of support & care.
If it is TE, the hair will grow back, it'll just take time.
Please try not to stress too much - just treat your body well, eat good foods, make sure your vitamin levels etc are ok, do some exercise.