All the signs are there .. Just won't show on a test !!

Me and my partner have been trying for a baby for 7 months . Only recently I have noticed that my belly is getting bigger , I've done loads of pregnancy test but they all keep coming back negative . It's very strange cause I'm getting tired easily, I've been feeling sick, I've been wanting certain foods and my boobs are getting bigger and are becoming very sore . I don't know if I am or not.