Some medications we use cause hair loss. There are other reasons for it as well.
You should go and see your doctor. Take some time and write down the the where's and whens of your hair loss so you are ready for what ever questions you doctor will ask.
Stress can also cause hair loss.
It's not as uncommon in women as you may think. I've had thinning hair most of my life so I'm used to dealing with it.
I believe there are some new options out there. I've been thinking of looking into them myself.
I'll be curious to hear what your doctor has to say, so keep us posted