Brown/pink watery period?!

Hi 

not really sure to where to start but was wondering if anyone has experienced the same as me and what was the outcome... I'll start from the beginning sorry if it is long winded! 

right beginning of December I came off the pill had my period on the 18th December normal nothing strange. beginning of January I felt like I was about to get my period again my breasts became very very sore, tummy cramps etc this last about 3 days but no period, then 2 days before I was due on (13th jan) light tummy cramps started again, breasts were still tender from beginning of the month thought i was about to have my period 6 days later tummy cramps gone and no sign of period. when I was 5 days late I did a test but it was negative so thought period would come soon I'm now 2 weeks late (haven't tested again) 3 days ago I started having a very little amount of brown blood/discharge and pink watery blood maybe 4 or 5 times but only after wiping, my breasts are still sore I'm feeling tired and waves of sickness for past week or so. I have 2 other children 6 & 3 and had nothing like this with them. I don't know if I should test again or if anyone has had the same experience and what was the outcome? I have no idea what my body is doing lol any thoughts??