7 days late

Need advice my period is 7 days late and since I've had my children my periods became regular. My daughter is 3 and my son is 9 months. I have been nauseous and very tired and my head has hurt for 3 days. My symptoms for both pregnancies were much different. The problem is that this child would have a different father since I've been messing with him for 3 yrs now my son is not his my daughter and son have the same father (did DNA to make sure) but this time I would have no doubt who the father would be and it would be a very messy situation. Neither one of us are happy with the ppl we stay with we both have 2 children a piece he has a daughter the same age as mine and his son is a yr younger than his daughter so we would have our hands full with all them children close in age. I was wondering if anyone has had the same symptoms and has had a missed period for 7 days and ended up pregnant.and I am on birth control but however my son is a birth control baby.