What Causes Tender Breasts And Lower Back Pain With HPT Negative?

hello im 23 years old and on seasonique sence october im not very good at taking them everyday and on time i was due to get my period in january and i never got it i called the doctor and he said it was fine but i never started taking my new pack for 3 weeks and i never got my period and for the past week i have been having tender breast and nipples and lower back pain and i took a HPT today and it was negative what does this mean