J.J.
It could be stress related.You have 4children one of which is still an infant.I'm sure you aren't sleeping properly/getting alot of sleep.And than normal everyday stress on top of that.
It's good you are getting checked out by your dr.But try to"relax"some.I know i have had the heart in the vice feeling alot and mine is all stress related.I have learned different relaxtion techniques(sp)and that has help.The biggest help has been the breathing to relax.
Try taking several deep breaths with your eyes closed and just relax..it really does help.
But please keep us posted.
J.