It's probally best to first find out the cause of the thinning in such cases it may be stress, or lack of nutrients the body needs. I'm not a woman but I used multivitamins from boots which contains 23 essential nutrients for the body and has all the vitamins required to grow hair such as vitamin B, B6, A, C Biotin, Zinc
Also try scalp massages as this definatly helps and circulate the blood in your scalp and to the hair follicles it then helps stimulate hair growth Can Scalp Massage Stimulate Hair Growth - Hair Loss Expert
If it is stress well i gess you just need to relax and do this
Another product i used is Castor oil, Now this definatly help thicken your hair and is worth using to see if it helps, you can buy this at your local shop.
Castor Oil: Hair Growth Treatment for Thicker and Healthy-Looking Hair | Castor Oil Uses
Here is a guide for other ways you can help regrow your hair, I hope i've helped don't worry your not alone
How To Regrow Hair