Brown discharge, 4 days late period, 2 negative preg test

[ches61]

Hi. I've been on birth control for almost two years and my period is  like clockwork well this time I am 4 days late and I PMS'ed really bad, I have had 3 migraines with really bad nasuea in the last week, everything taste off to me to the point where i get nausea with certain foods that i love to eat. but no cramping like normal.I also notice that if i go a while without eating i dont get a headache but i get really shakey and fatigued(eat lunch at 12:30 and by 4 oclock i'm shakeing for food and it's usually a normal lunch like salad and sandwhich) . I tested my blood sugar and it's normal.  I'm more tired than normal and have gone to bed when i got home and waken up just in time for work (meaning getting 13 hours of sleep). The last time my husband and I had sex was on May 3rd. today is the 17th. (my husbands leaves for business and is out for 4 weeks this time). I've had a brown discharge from time to time in the last 2 days and not sure what it means. I took 2 pregnancy test and the first one i thought maybe it was old becasue we're not trying to get pregnant and it was under my sink for about 8 months (the last time i took a preg test was when we went on vacation and forgot to take my birth control pills so had to not take it for that month). but then i bought first response knowing that it's more sensative and still negative. I'm not a stressed person, and i haven't changed anything about my diet, lifestyle. And i'm not stressed about being pregnant, I either am or i'm not no big deal either way i'm just confused as to what my body is doing and don't know if i should bother my doctor about it. I'm even getting nausea just typing this. Please let me know if you experienced this and what the outcome was. So many other boards are very confusing and provide really no decent answers. Help