Progesterone suppositories - front or back?

Er
Soo I just did my first IUI and the doctor has prescribed progesterone suppositories for me twice a day. I've used 2 so far and I already feel like I'm getting a yeast infection (has anyone gotten one from the suppositories??). We also had sex last night about an hour after the suppository and I just felt gross. Has anyone used them the 'other' way? Reviews? Any tips or advice would be much appreciated. Can't imagine doing this for the next 3 months.