Reddit reviews The Drowning Girl

Your post reminded me of reading Caitlín R. Kiernan's: "The Drowning Girl", whose main character is also obsessing over numbers. It's very good, but also a bit scary:

https://www.amazon.com/Drowning-Girl-Caitlin-R-Kiernan/dp/0451464168/ref=asap_bc?ie=UTF8

The King in Yellow was arguable Lovecraft's biggest influence.

Mervyn Peake's Gormenghast books might be a good fit.

Haruki Murakami in my opinion does "dreamlike" better then anyone else I have read. The Wind up Bird Chronicles, might be a good start.

For something like Stardust, I would recommend John Crowly, particularly Little Big, Winters Tale, and maybe Jonathan Strange & Mr Norrell.

I think Clive Barker hits the tone you are looking for sometimes, but not in all of his work, maybe someone who has read him more can give a better recommendation.

If you have not read China Miéville Perdido Street Station would be a good start.

I just started The Drowning Girl so can't really give a full review, but so far it seems like it would also be a good fit.

For something that is not really what you asked for, but is a fun read for a Lovecraft fan I would recommend Charles Stross' The Laundry Files Series, Starting with The Atrocity Archive A semi comic story about the bureaucratic side of the secret agency that deals with the impending lovecraftian nightmare apocalypse, a little pulpy, but lots of fun.