Lots of teens - girls and boys and all identities - hump pillows. It's a common form of masturbation. You aren't sick, you aren't alone.
https://www.bishuk.com/your-questions/humping-a-pillow-is-it-normal/
I wouldn't recommend searching for this though - I got many, many, many porn links.
I wish I could do that to celebrate my first day being 13 but as we all know I'm a stupid boy
Yes, it is perfectly normal for you to hump your pillows and blankets, I've been doing it since I was at least three years old and Im 21 now and I can't ejaculate any other way. For instance, I can't use my hands, because it just doesn't work that way for me and I've tried a number of times to do it that way but it just doesn't work out for me and ever since I was little, I was humping then and I'm still humping now and that's how I'm going to do it for the rest of my life, but anyways, my mom believes in no sex before marriage, but she was perfectly fine with me humping as much as I pleased, and it's technically not sex since what your humping isn't a person and, it's your body and you can do whatever you want with it, but I would strongly recommend making safe and smart choices about it and make sure the door is locked so that way you can have the most privacy as possible and you're not sick, your just experimenting with certain things and before my mom and dad found out I thought that it was a big dark secret too, but after my parents found out it was no big deal, but everybody's parents are different and so I would proceed with caution if you do plan to tell them and after you explain your feelings about that subject with them they should be understanding about it, at least my parents were but when you do hump something, remember, the number one rule: to always have fun! I hope that this helps you out with your situation