What Causes Abdominal Cramps While On Progesterone Suppositories?

Hi, I am 39 years old and will be 6 weeks pregnant Saturday. I had an IUI done on February 13th--this was not due to infertility issues really, it was due to the fact that I have painful bladder syndrome with flares during ovulation and therefore was unable to try naturally with my husband during ovulation. My concern is that my doctor, a fertility doctor is very used to treating women with fertility issues and so he didn t just check hcg levels, he checked progesterone too. I was checked at 4 weeks 4 days (hcg 1589 and P4 was 14) and again at 4 weeks and 6 days (hcg 4,027 and P4 was 11.4). My doctor then put me on progesterone. I wasn t sure if I should take it but when I asked him about it he was very agitated and told me that there was no difference between the pill and the natural form your body makes. Well, I was not comfortable asking anymore questions. So I m here for help...I just started taking the pills 3 nights ago. They are 200 mgs to be taken orally. Now I have some cramps. I ve researched and I m scared that it may be harming my baby. So I would stop but I ve heard stopping is dangerous too. My question...should I continue this pill? If not, should I take one every other day to wean myself off gradually or is just taking them for 3 nights not enough to be concerned about stopping completely. I went to my primary care doctor today but he said he didn t feel he knew enough about it to give me advice. Any help would be much appreciated. Thank you!