late? pregnant?

Hey guys ! Soo I have a little dilemma ... my period is normally a little off by like a day or two ...  but as of today  I'm 19 days late ... I've taken numerous urine tests all negative ... in going to my doctor next week for blood work if my period doesn't show Up before then.  I have to boys (ages 3 and Almost 5) we've been trying since July 2016 to have one more ...   I've been able to smell everything ...  I keep thinking I start my period because it's like a small amount of discharge  but more then normal almost like a small gush (as if I were starting my period) but it's not my period and it's clear/watery/white no weird odor ...