hi im currently 13 days late for my period but hpt shows negative. i have been 'cramping' for 15 days, lower back pain, nausia, sore breasts. I knoww from previous scans that i have a cyst on my ovary. is it likely this is playing up rather than being pregnant? i am 33 and my previous pregnancy showed up negative on 6 hpt until i was 6 weeks pregnant, even at doctors! help!