You sound like a very strong Empath I cry at pretty much anything to be honest; disney movies at parts where is doesn't even make sense, tv ads, seeing people that are sad. I am sorry to hear about your marriage, but I am glad to hear that you are getting help! You are not only just imagining yourself in their shoes, but you can feel how they feel that same second, along with how you'd feel if you were in that position yourself. I have also always questioned big life questions from a small age, but it always seemed so necessary to question it, you know?
Now, I would not necessarily say that you are becoming more aware of it because of the Reiki, though it could play a part, along with the meditation. I feel like those things are helping you to become aware of who you actually are inside. And it's like you have been repressing it sort of, and now it is all coming to the surface.
I have had many of my pets die, and I will see them in my house at times, just rubbing up against things like they normally would. And I think they come back to remind me that they're there and that they miss me. So perhaps your grandmother was missing you and decided to make a visit. I feel like maybe she wanted to reassure you that she wasn't actually gone, and wanted to give you a 'see you later' hug.
How to proceed? I recommend you talk to Trevor Lewis here about an emotional clearing. See how that goes for you. After that, embrace yourself and who you are. We all have such little time here and it'd be a waste to have to constantly push your true self away. Also, you will often find that people with issues will come to you for help. Now, they may seem like they want to be friends, and perhaps some of them do, but many people are drawn to us like a magnet. Their soul likes our souls and they know that you are a safe spot and they can get the help that they need. I say that to an extent you should give them help. Never drain yourself out because you are trying to help them. Especially if it is just all about drama and more drama, those people are just so caught up that they want you to get caught in it as well. So, just be wary is what I am trying to say.
If you would like, I can send you some info in your inbox for protecting yourself while in public. That way you don't get home feeling confused, anxious and basically like crap because everyone else's negativity has clung to you whilst out. I really hope all of this helped I can send more info if you'd like!
Lots Of Love,