Progesterone supplements

Kerri • 17 months ttc, 4 cycles fertility treatments just got my + hpt today!!!
Has anyone used progesterone cream, or supplements after ovulation without a doctors suggestion? I'm really believing that I have low progesterone, and that little extra boost will help. I just got a positive wondfo lh yesterday. I see my regular doctor tomorrow, I am going to ask about hormonal blood tests and also supplements. I would really like to try while I'm waiting to get into the fertility clinic.....
​Also what blood tests should I ask for? I was thinking estrogen and progesterone for sure, but what else? Thyroid? And I wouldn't go for the test until 7 dpo( or my + o test right?)