Pregnant? Help.

I've been experiencing

1. Lower back pain for almost 2 weeks.

2. Nausea and vomiting for a week and a half

3. Diarrhea and constipation for a week

4. Really fatigue for a week and a half

5. Cramps for almost two weeks

6. Period is two days late but I'm irregular.

7. Tender breasts a couple times

So far I've only had negative tests. My best friend went through something similar and is 18 weeks

Feedback appreciated. Thanks.