Advice, thoughts?

So a few days ago i got some dark blood but very little and only when i wiped, the next day the same thing but a sticky mucus light pink and it was even lighter only a little when i wipped. Then that night i had a complete melt down for no reason i started crying hysterically because my husband was messing with me but i just felt so overwhelmed i guess i have no idea.. and since then i have had no bleeding at all but still feel emotional and sometimes get nausea....but ive taken two test and they are negative...my period has not come nor do i know when its supposed to just know it comes every month around the end of the month??? Could i still be pregnant? Could of been implant bleeding? How long after that should i take a test