so you're saying your last period was april 3?
in which case the likely date of conception based on a 28 day cycle would be april 17 giving a due date of jan 8.

but you say your due date was dec 30 which means a likely concpetion date of april 8 (and a last period of march 25).

your period of high fertility is in the 5 days before and including the likely conception date.

what date was the baby actually born?

baby was born on the 31st of december 05 so im not sure if my last period was an actual period or not

well, your conception date is most likely to have been around april 8.

i just dont understand it as i had just fineshd my period on the 8th? and didnt have sex until the 10th.
could it be possible i was pregnant and that was not a proper period? whitch means i may have conceived just after the 22 of march?

no, that isn't possible.
your baby was born almost on his/her due date.
a dating scan which measures the gestation very accurately (but allow a day either way) put your due date at dec 30.

so while your periods might be irregular and your april spotting/bleeding may not have been a proper period, you almost certainly were not at that point already pregnant.

to be due on dec 30 and have a full term baby on dec 31 means conception is most likely to have been april 8/9.
that means any sex you had between 4/5 and 8/9 is what got you pregnant.

if you are 100% sure you didn't have sex until april 10 then that is probably when you got pregnant (allowing for a day out here and allowing for a day either way on a dating scan).