My Rocky(D) raped me

I am a 13 year old girl. My mom has a big Great Dane that licks me when I sleep. One day when my mom went to work early I woke up to a wetness between my legs and when I looked, my moms Rocky(D), Alex, was there licking my vagina. It felt good so I let him but when he got rougher and started to stick his tongue in my vagina and butt-hole I tried to stop him but then he growled and acted like he was going to bite me so I thought that maybe he’d stop on his own. When he didn’t I moved fast and got off my bed. He then got down and I thought that he was going to leave. He jumped on me and knocked me down on all fours and got on top of me. He’s really heavy and I couldn’t get him off of me. His penis touched my leg and that’s how I realized that he was mounting me. It started to scare me so I started to try and crawl forward but he growled and bit my butt cheek, not hard enough to break the skin but hard enough to stop me from moving. He thrust his hips forward and his whole penis went into my vagina, it hurt so bad that I cried. He picked up his pace and he kept going for about seven minutes until he thrust one last time and his knot went in, it hurt worse than the first part. The knot started to swell inside and me I could feel him cumming inside me, it was mostly pain but there was just a tiny bit of pleasure, so small that it was almost non existent. He was panting hard. I thought he was done so I tried to move only to realize that he was literally stuck inside me, it scared me to death, I didn’t know what to do. I tried to pull away but it hurt, plus he growled at me. We were stuck like that for about 35 minutes. After we separated, his cum was flowing out of me and I had to rush to the bathroom. After I cleaned up, I locked him out of my room and I cried because I had lost my virginity to a Rocky(D). He now does this often, especially when I’m on my period, why is this? I hadn’t told my mom or anyone in my family about it, so I put it on here. If you have any ideas on why he does this, please comment.