I stopped taking pill 6months ago still not had a proper per

I stopped taking the pill in July and then had a proper period as normal after i finshed my packet of pills since then i had another period about 28 days after my last period so i thought all was good and then nothing since about December when i had spotting for a couple of days, now after xmas i had spotting again for a day thinking i was at last getting my period but half way through the day that was it nothing more, i have taken several pregnacny tests but not for a couple of months, but all shown negative, we are trying for a baby and i am just wondering is this normal. Hope some one can give me some advice.