Please help, so many mixed signals!

Okay so I'm a week late for my period and I have been TTC for almost 3 months now and usually I just get cramps the day before I start, but the past 2 weeks my breasts have been swollen and really tender to touch and they look darker, I also have a dark line down my belly which I've never had before, I've been cramping off and on, super tired and just nauseous a lot, any ideas of what this means ?