Missed period, lots of symptoms, negative test?

Ok so i am on the pill and took it every day, i had sex a few times. I was expecting my period a couple of weeks ago, it was a sunday i was supposed to get it, and nothing came! Then wednesday i had a tiny spot of blood! Then nothing, so the next day i took a pregnancy test. It came out negative, but then i read afterwards your not supposed to drink loads and loads so you need to pee,then take it, and thats what i did. but i thought i will be fine, but the past few days i have been peeing loads, i have put on weight recently, getting dizzy a lot, tired more often and feeling sick, and going off food! So what do i do, really need advice! Very Very scared! 🙁