Steam download takes 2 days for a 4GB game?

A friend is staying over at my place today, and we wanted to download some horror games for Halloween. My boyfriend created a new Steam account a few days ago and logged into my PC with it. He bought the games Granny Remake (1.8GB) and Don't Scream (4GB). We wanted to download Don't Scream, but it's extremely slow—only 150 Kbit/s—and it says the download will take two days. I don't understand why it's so slow, because my PC downloads are usually pretty fast. The Wi-Fi is working fine, too.

Does anyone know why this is happening because we would really like to play today.

LG