Help what could this be!?!?

Me and my husband have been trying for a baby for about 3 weeks now and I’ve been off birth control for 2. I had my period but it was super light except for 1 day. Then I’ve been nauseous, having small pains, overly exhausted, and some diarrhea (TMI I’m sorry). I took a test and it said negative but today I’ve started throwing up and my boobs have started getting some pain in them as well.