Shropshirelass, so sorry to hear this, it is rotten. Maybe you are reacting to the estriol cream. I have in the past found both the creams stung like blazes and had a similar reaction to Ovestin (although OK with Estriol Cream now, so there is hope).
Have you been swabbed for infections such as thrush and BV? These can result in a lot of soreness.
I'm wondering if a 1% hydrocortisone cream or ointment might get the inflammation down. You could also try a well-wrapped ice pack, or a little MultiGyn Actigel. Have you had a look at the area?
What I did was to use an Estring only for a while, then reintroduced Vagifem along with some Yes VM to make sure it dissolved. In that way I could rule things in or out by not using too many products.
I can't think what else to suggest for your immediate problem, but I guess a trip to the GP or nurse might be in order for Monday.
JP x