Could i be pregnant even though i am lightly spotting?

Patient: Please help. Today is day 5 of no period. I have just now noticed some very light spotting. i am always on time and am on the nuvaring. I was on antibiotics at the beginning of the month and my husband and i had sex on the 9th and 10th. i have noticed an elevated temperature for a few days straight, heartburn, looser stools but only having bowel movements around 3 oclock in the morning every night, feeling nauseous after. headaches every morning, lower back pain and slight cramps. i have taken 2 home pregnancy test both were negative. Could i b pregnant?