Heart palpitations and vomiting sensatio

Iam the mother of 21months old baby with delay walking milestone. Before two three months suddenly one day I felt heart rate above 100 and vomiting sensation all the sudden I heard my heart beat sound.two months now and then it comes and goes and made me fear as of I would die I had loose bowl movement too. I checked my whole health and ecg echo( MVP Aml,mrt)and all other reports were normal.no thyroid too. Dr told there is no prob all because of stress.i was in stress because of my daughter delay walking and my hubby used to show his office tension . Now Iam taking concor 2.5 bisoploler and lonazep 2.5 everyday for past one month but even though now and then I feel heart rate high even after my daughter starts to walk too. What should I do how can I come out of my stress