Question-LH -short protocol-Metformin

Dear doctor,
I am 35 years old, have gone through 8 ivf cycles, no pregnancy. At beginning e2 92, fsh 7,1, lh 9.5, amh 1.39. No PCOS. Early regrutation, I suppose DOR. From the start poor response on short protocol, follicles unsinchronized, 1-3 eggs (Fostimon; clomifen+Fostimon). Best results on long protocol (with Diferelin + high dose Menopour, 6-7 eggs, few good embryos). However I used Dhea and eggs got worse (after reading your texts I understand that was mistake). Could you suggest the best short protocol for me?
One more question. I used Metformin for 6 months, as my results revealed insulin resistance after use of dhea. All of the sudden my AFC drastically dropped, and my reaction in the latest IVF cycle was so delayed and slow. Eggs fertilized but embryo arrested very early. Please, could you answer me, do you think that Metformin so drastically changed my endocrine levels, that I went to opposite thing to high androgens (provoced by LH)? Thanks indeed.