I am a little worried I may be pregnant.. Yet the test was negative?

My symptoms are as following: Insomnia, nausea, gas, restless leg syndrome, frequent urination, stomachache, I thought I got my period; however, it was lighter than it ever was and only lasted four days and I've never had that before, bloating, my breasts feel swollen (gotten bigger), I also seem to be getting very tired lately. (napping more than usual)Back pain like I've never had it before. Mood swings, I can't even look at some food. And vivid dreams I've never had before. I took a pregnancy test and it said it was negative. It's barely been three weeks since the conception however. I'm new to this sort of thing, so I was wondering if someone more experienced could assist me,