Ok, EMF indications in a Bathroom or Spamalamadingdong will naturally spike due to the amount of electrical appliances and added wiring in such areas and too, plumbing in that water flow and affect readings. Sensitive people will pick up on this same energy flux and misinterpret it as being "proof" that a ghosty is about when in truth, that's usually not the case; just the mind jumping to conclusions and with those that are heavy in their religious beliefs, assuming "the worse" is not that unusual.
Yes, being heavily motivated by way of our spiritual
(not religious) connections will make us naturally more sensitive to the etheric world around us. But what is really happening is that these connections are helping us unlock previously suppressed aspects of awareness, something that the religious sort will never come to know . . . one can be very religious and never understand the essence of their faith while people who never step into a church, temple or other place of worship can be exceptionally aware of things because of their spiritual sense of pragmatism. I know this may sound confusing at present but you're just starting down a long road to self-discovery and as such, you owe it to yourself to look at each issue from all sides, not just the side you want to believe in. To be fair and honest you have to understand this sort of phenomenon from the more skeptical side of things as well as the spiritual; it will prevent you from looking like the typical babbling New Age fool.
Yes, some people can and do attract the disembodied but that does not mean they are a "Medium" or even meant to work as a channel of some kind. Just as a porch light attracts insects at night so will a person's spiritual ties draw the lost and disoriented and at times, stronger more angry energies. Don't fear the latter, that's where they get their strength; your fear empowers them so learn how to keep centered and grounded when such things manifest. This is where that skeptical understanding comes into play as well, in that you need to look at such influences on a critical plane so as to keep your own imagination and religious ideologies from making this kind of phenomena more than it is.
Some people that serve in the capacity of being a "soul magnet" for lack of a better expression, exist for the sake of bringing the wondering entities to either an accomplished medium/sensitive so they can be taken to the light OR (and this is pertinent to you), so you can perform those rites that will help them find their way i.e. prayers, lighting the candles for these entities so they can be healed and able to let go of the carnal plane they now cling to. This is a very ancient and nearly forgotten (swept under the rug) practice found in certain older Convent work by nuns that were touched by spirits such as you describe.
Don't Waste Your Time playing with the EMF meter and your ability to raise & lower its readings and don't get caught up in the fantasy of becoming a famous or popular psychic of some kind. While I would encourage you to learn more about mediumship (from all sides) and spiritual work that lays outside church approved doctrine, I must encourage that you take it all with a large pinch of salt, balancing it with the analytical.
I've worked as a Psychic & Psychic Entertainer since the mid-1970s much of my work in the 80's being with noted personalities of the day like Louise Hay and Marianne Williamson, so I know just a little bit about this sort of thing and matters of the esoteric. I say this solely for the fact that you need to hear things from qualified individuals; people that have been on the path for many years and seen both, its truth as well as its lies. I hope that you will choose to walk that same path vs. embracing the phenomenal without having balance.