I had my period about a month ago, could i be pregnant?

I really need some experienced advice... The last few 4-5 days, after i eat.. i feel like i could throw it all up. I really cant sleep at night, but i have the feeling of being exhausted all day long. I have heart burn constantly, and only had morning sickness 1 outta the 4 days. I took a preggo test this morning and it came up negative. But i feel constant pressure in my abdomen area.. Could it be to soon for a test to come up positive. Also i was ovulating the 15-18th and had sex every day.. i could really use some advice please. And i dont mean to be TMI.. but ive had alot of discharge lately...