It is very unlikely that your hymen
would have been ruptured by pillow between your thighs rubbing on the vulva
. The blood you saw could be from some scratch on the skin of the vulva. Please have a look in the mirror. If the lesion is alarming, you may have to report to the Gynaecologist for some treatment.
And about hymen rupture:
In this era, the girls are working and having so many activities which can rupture their hymen without any sexual experience. Theses activities include cycling, sitting astride, horse riding, climbing on tree, athletics, etc. So now people are indeed not keen on the intact hymen. What is more important is attitude in the life.
I hope this helps.
Dr. Nishikant Shrotri