Missed period. Negative pregnancy tests

So I am now 6 days late. I've experienced morning sickness for the past 3 weeks, dizziness everyday, increased appetite, fatigue & insomnia, bloating..I haven't had cramps that feel like menstrual cramps, they feel more like gas almost. Its not happening all the time, just once in awhile. I've taken about 4 or 5 tests, 2 of them were very faint but the rest were negative. Any ideas on what's going on