I'm so confused.

Okay ladies. So I haven't had a normal period in the last 3 or 4 months. Most of the time they last maybe a day to a day and a half at the longest and are extremely light. It's almost like I'm spotting. I've taken numerous test (including today) and they are all BFN. I'm having pains in my lower abdomen and lower back. And I'm craving weird foods that I normally hate but my
husband loves. I've also been getting sick at night (always at the same time) and even some in the mornings. What do I do?!? 
All advice is greatly appreciated!