Luteal Phase

Stacey • TTC #1 for 5 yrs. MFI & PCOS. Aug & Sept 2016 IUI — BFN ❌. IVF/ICSI•10/27 - 0 eggs. IVF#2 1/29 - Fresh transfer of two 5 day embryos. Expecting twin boys!! At 28w we found out Twin A no longer had a heartbeat 💔
I am averaging an 11 day LP. Is this enough for implantation? O on CD 18-19. Any thoughts or successes from those with a similar LP?