When should I test again; already had one negative!

Hello, ladies! I could really use some advice! My typical cycle length is 30 days long; AF is usually on time within a day or two of what the previous month's cycle was. Ex; one month AF comes on CD22, the next month CD, and the month after that back to CD22 again.
​Well, this month I did the BD on every single day of my most fertile days (March 5-11th).
​On the 19th of this month... I randomly went pee during the day and there when I wiped was quite a bit of super light pink (what looked to be CM). It was that one time only on that day and hasn't came back since. But... on the 20th &21rst I had very bad headaches and came home one day; slept 13 hours into the next day! I also have had cramping on and off to one side; I had an upset stomach a couple times after eating, dizziness, exhaustion and peed three times in one hour only after drinking a glass of water. I took a test on a first response yesterday and got a BFN. My period as of today is late. Tomorrow will be two days and still no feelings it'll show? I have a weird fluttery/jittery feeling in my stomach. Also loss of appetite.
​Could I have had implantation bleeding? I've never experienced this randomly pink before. Could I have tested too early? I could really use some advice please? (: