I don’t want to invalidate your experience or your feelings on the topic, however I would like to offer some logical insights that might apply.
You haven’t offered any details of consequence, other than to say that you had “a very bad experience” and one night / early morning experienced “something quite horrific”. (Perhaps both of those phrases refer to the same thing.) You also didn’t say anything about exactly how long you had been in the hotel or any other details of your trip. (I presume that this was a trip, and that you weren’t in a hotel in or near your home town.)
All of those things can be related to the travel. Most of my travels these days take me to the opposite side of the world, to India and Malaysia specifically, lately. Aside from the exhaustion of the travel itself – normally 19 to 25-hour trips, door to door – when I get there I’m on “the opposite side of the clock” from where I should be. I’ve had some of the worst nights of sleep when I’m most exhausted, and I’ve gotten tremendously sick (before I’ve even had “foreign food”, that is), and had some of the strangest dreams in foreign hotel rooms. In fact, my first night in a hotel even in the same time zone where I normally live is often an uncomfortable and sleepless one.
I don’t attribute any of my problems to “the hotel” or “the country”. It’s part of the stress of the travel I have to do and the job that I’m traveling to perform.
And aside from dreams and nightmares (and I have had some amazingly realistic dreams of entrapment and physical restraint – a particular phobia of mine) as well as dreams of violence, revenge and retribution, which is no part of my normal makeup.
However, I have never even investigated the particular histories of the hotels I’ve stayed at. Most of them are old enough that I presume that extraordinary events have probably happened from time to time and place to place. I’m not predisposed to thinking in terms of haunting, ghosts and other psychic phenomena. I think you are, and I think that’s a big part of why you feel about things (unspecified things) in the unspecified way that you do.
Again, I’m not trying to invalidate you. Your feelings are certainly real enough, but I’m suggesting that the bases for them may not be as direct a cause as you may believe. But that belief feeds the feelings, which intensifies the belief. It’s a vicious cycle.