Sammiejane, I started off on Oestrogel and testosterone every day and took Utrogestan cyclically for a number of years. I don't suffer with hair loss but I did shed more hair than I do now on my current continuous combined regime.
Because you are very young and you don't have a womb, you probably need more oestrogen than me (I'm 58) but you have a lot of flexibility where progesterone is concerned because you only need it as a hormone stabiliser/balancer and not for womb protection.
In your situation, I would look at transdermal progesterone cream because it has fewer side effects. I wonder if 100mg Utrogestan is a bit heavy duty in your case? Have you tried Utrogestan yet and if so, how did you find it?