I have irregular periods and its very hard to tell the diffrence bettwen pms and pregnancy but lately the past 3 days I have felt very lazy and dizzy getting headaches on and off as well with back aches on and off faint cramps in my lower abdomen and what feels like pain near my belly button sometimes. Also if I get up from laying or after eating or drinking I will feel nausea but then it will go away and I will feel hungry but nor for a full meal and will just eat little things and allergy like symptoms stuffy nose sore sneezing... nipples seem a little sensitive but no sore breasts, could I be pregnant and I also don't know when I should take a pregnancy test if I might be considering my periods have always been irregular, thanks for the help.

Try taking a test tomorrow morning. If your symptoms continue, you could test once per week since you're not sure when your period is due.

No way to tell, actually the majority of women never get any pregnancy signs till they miss a period ( or two) so with irregular period it is even harder to know.

So taking a pregnancy test, using first urine of the morning is the only way.

So you may want to even wait for a couple more weeks, see if you get a period or not and then test.