I did alot of investigation work on progesterone... depending on what study you read... some yes it will help you from m/c.... others say you have low progesterone because the pregnancy will fail anyway. It all depends on the study..
As for your history.. your periods sound alot like what mine are when my body is "normal".. After my losses.. sometimes it took 7 months to get back to "normal".. With that being said.. thier was alot of months that I swore I was pregnant.. and never got a + hpt... so I know I wasn't. Even with a "chemical" pregancy you will get a + hpt...
I know some ladies swear they never get a + hpt... I am not sure I buy it 100%. When you are pregnant.. you start producing HCG. HCG goes into you blood and urine. Yes I am sure.. thier is times when their dates will be off... but I would like to see medical article... not it happened to my sister's, cousins, aunt.
I know for me... After 3 confirmed losses.. My Dr said progesterone can't hurt.. can only help if that is the problem. So he was going to put me on it after ovulation on the next cycle (that would have been Sept).... But I got a BFP in Aug... only to m/c my numbers never doubled. When I went in for CD3 blood work and u/s in Nov first cycle after my m/c.. It was shown I had no mature follies that would release an egg.. I was than put on clomid... and my Dr always puts you on Progesterone while on Clomid since clomid can break down your linning. After my third cycle.. I got my BFP.. (Like Kat said.. I also stoped taking my Baby aspirin prior to ovulation)..... I have been on the progesterone since ovulation..
Here are some links.. to help you make a more informed choice..
Progesterone - Using Progesterone to Prevent Recurrent Miscarriage
Causes
The Misdiagnosed Miscarriage :: View topic - The importance of progesterone and progesterone supplements
After everything.... My Dr said it best... It can't hurt...