I just don't see how you can accidentally take that many pills. As I said earlier, it isn't as much of a stretch but it is still a stretch.
I do think Morgan had some problems of her own. If she had porphyria that could be the cause. If she was poisoned, that could be the cause. She was also prescribed a good bit of meds and was apparently in a lot of pain. She was anything but typical. If she did not think there was a stalker herself it just seems like she would have said something to one of her friends. One of them would know if it was all bullshitting and they would have said something by now. It's hard to think they would just sit back and let this shitstorm brew knowing there was nothing to it. It could be possible but the simplest answer, no matter how unappetizing, is usually the correct one.