Do I have OCD(Obsessive-Compulsive Disorder)?

I'm beginning to think I may have OCD. Recently, I've been getting into a compulsion of straightening things. For example, I was going to a friends' house, and after ringing his doorbell, his doormat was on the left side so I centered it accordingly to the door. If I don't, it will bother me and I will become more irritable. Another thing that tends to bother me are notifications. For example, if I have message notifications on Facebook or other visible notifications elsewhere, I must check what is there so that I don't visually see the notification. Like if I got a message, I'm compulsed to read it so that I don't have the notification anymore. If I do not take care of the notifications, it always ticks in my head that I must do it, and I start feeling uncomfortable and really aggravated. Another thing is that I keep thinking about cruel or inhumane acts in my head. I sometimes keep thinking about violent and cruel stuff that I will never ever do, like cutting my dog's tail off. I really love my dog, and I'm constantly afraid that this will drive me to hurt him, which I will never willingly do. I cannot control these thoughts and it is bothering me. Also, I repeatedly check whether I unplugged electrical things or turned off appliances or else I feel very paranoid and scared about what will happen to the safety of myself and the house. I do not have any problems with germs, however.