Am I going insane lol

I've had severe depression and anxiety all my life, im 18 years old and it keeps getting worse day by day and now its got to the point where Im scared of everyone, when im on my desktop my little brother sometimes gets in my room and i'd feel like hes gonna backstab me in the neck, hes 8 just to add to the weirdness, when i sleep i feel like someone is gonna murder me as well, whether its one of my families or someone completely random and it ruins my sleep cause i keep opening my eyes telling myself someone is about to murder me... Is it just me finally losing my mind or does any else have this same experience? Will this go away or just keep getting worse if its untreated?

You are not going insane and no one is going to murder you. You just have a lot of anxiety. At some point in time you may want to get treatment.