Something's got to give

Okay so... 16 weeks tomorrow. Other than my full term now almost five year old this is the longest I've carried for. He is going to be the death of me. I've posted about this before, but this pregnancy has been anything but kind to me. I spend four hours in the ER again today for clotting. Second time in 4 months of pregnancy. Again they can't find anything wrong! No blood left behind either! He is fine! Heartbeat still in the 160's, he is moving great, and growing! (He now has a penis which he had NO SHAME in showing the ultrasound tech!) They did blood work, urine test, ultrasounds, checked the cervix, You name it they did it. But again just like last time he is FINE! Don't get me wrong I am absolutely blessed that he is okay! But what the hell is happening to make me pass clots. And they are OLD too. Like brown and look like a clump of sand? If that makes sense. I'm losing my mind and my son may just give me a heart attack...