What Can Cause Tingling Nipples,slight Cramps,headaches,dizziness And Tiredness?

my period is allways on time and every 28 days,got a heavy period 5th of January and had what i think was another period on 2nd of Febuary which was very very light,brightish pink then a brown in between and lasted 4-5 days still very light..after it went i started getting tingling nipples,slight cramps,headaches,dizziness,tired than normal...but two weeks before my light bleed i had all these symptons which i thought was my period coming on...ive still got these symptons and im not due another period until 2nd march..ive took 3 home pregnancy tests and all are negative...did i have what you call implantation bleed and thought it was my period?and why have i got all these things going on with my body?feel pregnant..we have been trying for a baby!!!