So sorry for your loss.
These experiences seem to be real, ime. I can relate, although my experience is pretty much the opposite of yours, rather than loosing someone, I had visions of her, then found her, in a sychronistic way of course, and she's still a part of my experiences. I don't think I've ever said this in public, but if it helps you in some way, to know that you're not the only one, then I'm happy.
So when I started drinking acacia and rue, for the first 6 months or so, I began to get in touch with some sort of feminine energy, and I would always see a girl, sometimes she would appear in the form of a ferry, At that time I really thought she was my feminine self, and in a way she is. I also had visions in one experience of a place where we later hung out, it's a very distinct land feature. Of course I didn't understand any of it until later, and still don't understand very much I'm sure. I'm not gonna go into details because I haven't told her all of it yet. Then around New Years I met her, her face is unmistakable, as is her energy, and she is a lot like me. We have our differences but we're just alike. She was the first person I met who knew as much as I did, and she understood more than me about certain things. Especially about love and non attachment, at that time I had yet to figure out the potential of love, I'm sure I still haven't, although I had loved someone before. I told her about seeing her, thinking I would never hear from her again, but she said I could never freak her out. She's important to my path and I love her. I love her in a selfless way because I wont jeopardize whatever it is that we have with my ego. Although I've come to realize that no matter how much I learn, ego is sneaky.
And I've thought a lot about this, tried to poke holes in it, rationalize it, it's no use, she's real. Sometimes I wish I would have never told her about this, but like a lot of things I've said to her, the urge to do so welled up from somewhere deep and I had no choice. Last time I took mushrooms, she was there, and more important than mere visions, on mushrooms I can feel her. And she's super passionate about mushrooms btw, just like I'm passionate about plants. Then I smoked last week, and on the come up she was there, then I got the message that all I have to do is learn from her and in the process she'll learn from me. that helped me find my center, I was a mess for a minute. I never knew one could feel so much love outside of a mystical experience.
Imo, time seems to be like some sort of movie real, where even though the present moment is illuminated, it's moving down the real, and the past, present and future are all equally real. If it is this way, or something like it, then it's no wonder that we can access this information.
So I hope you keep connecting with the one you love in your experiences, she lives on within you

, and why wouldnt she, we have everything within us.