feeling different

My husband and I have been actively trying for about 8 months now. Finally about last month I started having what seems like a normal period. We have been having sex and about a week ago I felt something different. Lately I have been sooo tired and extra emotional. I have been getting these weird sharp muscle spasms is what it seems like in my pelvic area. Also for the past 3 days I have been feeling like I have butterflies in my stomach. And feeling very anxious as well. I'm also feeling like a bottomless pit! I have taken 3 tests and they are all negative. Today I woke up puking and puking and had to stay home from work. Has anyone felt anything like this and get negative tests? I did buy the multi pack from amazon I'm thinking getting a better brand?