6 yrs and counting!

My husband and I have been trying to conceive for the last six years. Though it has been on and off again we tried a couple months ago (taking ovulation tests) and trying to plan it. I've taken two pregnancy tests in the last month and they have both been negative. I'm not one of those people that normally hopes and tries to convince myself that I'm pregnant (that's why I use the digital tests) but I've had a lot of nausea over the past couple of weeks and my nipples are sore today. I'm four days away from my cycle date so I took another test and it was negative. I've never had symptoms like this before but again my test was negative. Anyone have any similar experiences?