If breast fed baby sleeps through the night 6-8 hours, is it still normal to have irregular periods?

Yes: Some women stop their periods completely until they stop breast feeding all together. Others, the periods may be irregular or resume a normal schedule. Ovulation is not predictable, so using breast feeding as a form of contraception is not recommended. Enjoy a good nights sleep. You deserve it. If you think you could be pregnant, a test will clarify that for you.