You may be pregnant. I have three children and the experience. Even doctors don't always know. Pregnant with my first they didn't find out until I was three months along. My second, I was five months along before their urine test declared pregnancy. Luckily my third was right on the nose, however, I was already three months pregnant. Still, we cannot simply rely on pregnancy. Us women, built so unique, have "wonderful" hormones that make our bodies do crazy things and act in crazy ways. Stress is another reason to skip a period as well. Don't worry yourself too much there is more signs of being pregnant other than missing your monthly visitor. Such things are, nipple tenderness, vomiting/nausea or even tenderness of your lower abdomen. Hang in there and just know if you happen to be pregnant, it is meant to be.

Honestly, no one here can answer that - you need to make an appointment with your ob-gyn. They will be the only ones who can do additional testing to see what might be going on. There are many things, other than pregnancy though, that can make your period be late - including stress, being highly active in sports, certain medications, etc... so definitely a good idea to get a check up.

Sometimes pregnancy tests are wrong. I once watched Mystery Diagnosis where a girl had all symptoms of a pregnancy (except her stomach barely grew), and she had taken 5 pregnancy tests all negative. 8 months later she had a baby. I would recommend go seeing a doctor for a check-up.

You definitely need to see a Dr., those tests aren't always accurate.