Pregnant and Breastfeeding but Tests say Negative?

[supermom1130]

Hi, I have a son who is almost 3 months and exclusively breastfed. Last week I began to experience nausea, headaches, and hot flashes. Today I vomited in the morning, nausea all day, headache, hot flashes, and really dizzy. I took a pregnancy test today and it said negative. I really think I am pregnant though. We had sex for the first time after baby was born 5 or 6 weeks after.

Is anyone else going through something like this? I feel like I am crazy when the test is saying NO but I feel PREGNANT