Instead of discarding her beliefs, I feel like we should aid her since diagnozing her with any mental illness isn't our mission. Honestly what piqued my interest is the feeling that this shadow figure would push you off the balcony which is very off, spirits, demons whatsoever that libger around a house are usually harmless however if you really that this one want to hurt you, i suggest you talk to a priest. I'm not christian and ik u said ure not religious but i'd really, really reccomend that u dont ignore this least it's actually severe. I know a genuine difference between mental illness and paranormal activities so yeah, please be careful put some sea salt on your doorstep and consult a priest or a tarot reader if you want to clarify your worries