Implantation for 4 Days? Possible

I had gotten my 'period' 6 days early which never happened, 
​First day- brown spotting 
​Second day very very light period red/pink
​Third day - only bled once brown/red/pink
​Fourth day - one brown spotting
​. This was a very unusual period for me 
​Taken a test on third day but negative 
​Today I had slight needle cramp kind of a feeling on my right lower tummy.
​I really would appreciate if anyone would like to help, 2nd month of ttc so all new to this stuff thank you