What Causes Delayed Period, Cramping, Sore Nipples And Nausea?

So I am trying to figure out if I could be pregnant. My period is almost 3 weeks late. I am normally on birthcontrol, but my pills got messed up. I was off them for a month. Didn t wait for my period to start before starting another pack. Took those pills for a month, but didn t have a period, and didn t start another pack. It s been almost 3 weeks since then. I ve been cramping a bit, but no blood. My nipples are sore, but my whole breast isn t. I am not nauseous now, but I was for about a week and threw up once. My food has been tasting weird, but no cravings. I also have headaches and fatigue. No back pain, no spotting. Slight mood change, but nothing severe. I m trying to decide if this is just PMS or I am pregnant. Thanks