What are the odds of showing signs of pregnancy but not being pregnant?

For the past three weeks I have showed many signs of being pregnant. Like nausea/vomiting, frequent urination, mood swings, breast tenderness, back aches, and I have the dark line down my stomach. But I've taken 4 pregnancy test and they all say negative. I'm confused. I already have a daughter and with her I knew I was pregnant. But I just don't know with this one.

Have you seen a doctor? they can give you a blood test and tell you for sure!

It usually takes 14-21 days for a urine pregnancy test to register as positive because your body needs to start producing the hCG hormone in adequate amounts. However, if you go to your doctor, they can tell you positively by running a blood test, which is more sensitive to lower levels of hCG than the urine test.

If you want something bad enough your body starts to react accordingly. Believe it that you're not pregnant and I bet you all your systems will go away.

it is very likely. Its happened to me. Some signs of pregnancy are just normal signs of a womans body anyway. But besides that, although you need take notice of these signs, if you are worried that you might be pregnant, you could actually make your body produce these signs out of stress. However, if you want to be pregnant and your getting these signs, maybe the tests were wrong....just gotta ride it out unfortunately, doesn't that suck....

symptoms of pregnancy begin 3-8 weeks after conception. i would check with a doc to see what's going on -- he/she will do a blood pregnancy test, even though at this point if you are indeed pregnant, home pregnancy tests are sensitive enough to detect hCG at any time of the day, not just in the morning. if you're stressed out in general, the stress is taking a toll on your body. once there's stress, your body will say no to kids and yes to all sorts of aches, pains and nausea. plus if you're drinking a lot of caffeinated drinks, that may explain your frequent urination.