I was lying suddenly I feel like I missed a heartbeat. After that I was sweating and my stomach ache and I had to go to the bathroom. Bp is normal.

A "missed" heartbeat is just a PAUSE after an EXTRA heart beat! Its called a "Palpitation" and the MOST COMMON CAUSE is ANXIETY!! Anxiety from the palpitation results in more palpitations! COOL IT! BTW "Lying down "waiting" for it is the best way to PRODUCE them!! Hope this helps! Dr Z.