The Missing Person's Guide to Love

I may have mentioned here before that one of the things I find slightly irritating in a book is to turn over the final page and find I am faced with pages of reading group questions. It has always felt a bit intrusive to my swirl of thoughts as I close the book. I know it's easy enough to quickly shut the book and ignore them completely but they catch my eye and then I'm thinking someone else's thoughts not my own.
So I can't really explain why I was desperately really hoping to find them as I turned the final page of The Missing Person's Guide to Love by Susanna Jones.
Fickle is me but I ended this book in quite a quandary and in need of help. I just couldn't figure out what had happened at all.
It wasn't because I was reading too fast either because I'd realized things were getting complicated so I'd slowed down and back tracked trying to figure it all out.
The blurb says
"As Isabel's world unravels we finally realize the stunning, shattering truth"
Now I'm feeling like a bear of very small brain indeed and I hope someone else will read this soon and help me out because I can't sort out who's alive, who's dead and who might never have existed in the first place.I've ended up with so many possible scenarios that I'm wondering if that's all a part of the whole and I'm supposed to be confused.I've gone back to the beginning and I'm desperate to find out what went on.
The truth hasn't dawned on me at all.
Taking all that into account you may be surprised to know it's a good read.
The lifelong effects of the sudden disappearance of childhood friends, impulsive adolescence and its consequences all play out in a book that is well written and quite gripping.I was completely engrossed but now I'm feeling a bit stupid because it's probably completely obvious but I can't fathom it at all.