Took a Home Pregnancy Test as Well as Blood Test and they both came out negative!!?

my period isn't until the 27th of this month, so i still have 4 days, but since after my period last month i had been experiencing cramps every single day for almost the entire day (thats never happened to me before) also i've been eating alot and alot of things i don't usually eat, i've gained 10 pounds, when i'm going to get my period i don't get this way at all and i only gain around 3 to 4 pounds, i've been bloated, my boobs hurt and have had some lower back pain,.. the only thing i'm thinking if i got pregnant it could have been 6 weeks ago but i think that it would have shown up already correct.. unless it was another time.. i feel like i might be pregnant but i don't know what else to think or do, i just took a blood test yesterday and got the results today. i also took a pregnancy test yesterday just because i was curious. but also negative... what else could it be?? i don't gain weight this quickly and i don't think that the pregnancy test was too early it's been 6 wks. i'm just curious if anything like this has happened before, i have a craving for Mango juice and i don't like mangos. i've eaten things i think are disgusting or things i never liked. i know i've heard cases where a woman is pregnant and doesn't know till she is having the baby. i just don't want to be that person..