P.I.D...

Hello ladies, I have had bad pelvic pain on my right side for about 10 months and have been to multiple doctors appointments and nothing has been picked up until now, I am being sent for a vaginal/internal examination in the next few weeks. Yesterday I noticed I had a strange coloured discharge, it was a peachy colour which was dry and crusty (sorry for the tmi!).. I feel sick quite alot of the time too. I am on the pill so don't have a period, however the other day when I had sex, when he pulled out we noticed a thick, brown liquid on him from my vagina. Does this sound like P.I.D to anyone that has/had it? I am slightly confused as I have only had sex with my partner who has never had sex with anyone else and have been tested and clear of std's/sti's... But it says P.I.D is commonly caused by sti's, but could it be caused by any other infections other than sti's? Thank you ladies :)