i have a really hard time going to sleep every night . i am always thinking worse case scenerio and i terrify my mind to the point of thinking if i close my eyes im going to miss the "intruder" or the "attack" . Sometimes i sit on the edge if my bed for hours in silence, everything off as to not make noise, just to be dead sure the is no one in the house. Sometimes i freak myself out listening to the silence that my brain fills it in with voices?? this is really scaring me and i dont n ow what to do about it. am i just over tired? is this a thing to do with panic and worrying too much? ? or is this a case of paranoia?? not sure but scared!!
full on anxiety you will find that it comes and goes and it will be louder and quieter. i have had success usinf deep breathing techniques and trying to stay active like get outside during the day and go on walks be active as you can. also at nite if i cant sleep i read the bible but i try to find uplifting things or even a self help book if nothing else find a subject you like and read about it online til your just fall asleep with your ohone on your chest. it does suck but you are not alone many anxiety sufferers have what i like to call an ongoing conversation with my self that i pick up and leave off at random times but im not scared of it because i know myself and i know im mot a bad person i look at it as more of a self examination technique it all helps good luck
overthinking is very common with anxiety. its not paranoia. anxiety causes negative scary thoughts and its a process of thought control. a good thing to listen to on you tube is called detachment from overthinking or many others on anxiety, negative thoughts etc
a therapist can help too. dont letthe thought stay. switch to a happy one
maybe if you live alone you would feel more comfortable living with another person,.
take care 
Sorry you’re going through this. try a product called Magtein, it’s magnesium that crosses the blood brain barrier. it calms your mind. it’s in Amazon. I hope it helps.