tired of negative tests!!!

Me and my husband have been trying for 3+ months now and I keep getting negative tests but I literally feel pregnant. I was on birth control before my son and period has not been regular since. I had dark red/brown discharge no period for two months although I spotted lightly for two days. I have gotten symptoms such as gaining 5 pounds, motion sickness and constant nausea as well as cramps. I feel exactly same as I did with my first and nothinggggg . It's not driving me nuts but I'm confused really never had any of these symptoms before. Besides when I was pregnant with my son.