Wow, you're ambitious mg.
Yes, your short luteal phase might be due to coming off the pill so recently. I know ideally, doctors want patients to wait a few months after coming off the pill, but who wants to wait?

hopefully, you'll get your bfp soon or at least you'll get a normal luteal phase.
I actually tend to be on the short side as well, but I have no indication that it is because of lpd.
(oops, I edited this to say "bfp" instead of "bfn" - that was a mistake.)