What Treatment Should I Undergo For My Heart Problem ?

I am a 48 yr old woman with heart palpitations for about 3 weeks, this has been going on. I went to emergency had blood work done and ekg ... nothing wrong. I am a diabetic..insulin dependent (Lantus) 22 units one time daily. 5/8 150 pounds. I have no shortness of breath , I again had a physical blood work fine...low on vitamin D. I feel like I am having some systoms of heart stuff, but is it in my mind? Dr did put me on Atenolol til she can rectify situation, stress test done on 4/30/11, no results yet. I am worried.