I took vit b complex, iron, vit d, coq10, omega 3 oil and normal prenatals. My lp was gradually getting longer when I got pregnant. 11 days isn't too bad if you can keep it around that. There's things you can eat too to increase progesterone. I didn't bother with this but I know green leafy veg was one of them. If you can get zita west's fertility and conception book I found this massively helpful