Viagra or other drugs to thicken the lining?

Dear Dr Potter,

Following an abortion at 12 weeks in March (my baby had multiples malformation), I had a FET planned on May the 26th. Unfortunately, we had to cancel it, because despite of 13 days under oral estrogen pills (6 mg a day) my lining was only 2.7 mm!

My next FET is scheduled end of June and I was recommended to had 2 vaginal pills of estrogen to the oral pills.

However, I am afraid it won't be enough to boost my lining and I want to do everything possible to help my lining to thicken.

I have read that viagra suppositories (sildenafil) can make a difference. Are you using it for your patients? What do you think about it?

Have you have other suggestions to improve the lining?

Thanks a lot in advance for your precious helps.
Best regards,
PP