Hi I Am A 21 Yr Old Male And I

Hi I am a 21 yr old male and I was diagnosed with neurocardiogenic syncope last year after being medically discharged from the navy because of fainting in bootcamp. I had a cardiologist run a tilt table test and I blacked out with extreme nausea at the 25 min mark. Well fast forward to about November of 2015 and I experienced multiple counts of blacking out. Two of the times was while laying down after having sex. They lasted for 20 to 30 seconds. In which I could hear my fiance talking but could do nothing to talk back. The worst part other than this was that I was in a fog with my chest hurting for the next day. I went to er after work which they ran the ekg. And showed nothing and they sort of chuckled at me. But I feel it's getting worse again. Upon standing I feel extreme nausea and dizziness. Any help would be greatly appreciated thank you!