Second Primary after HER2+

I was diagnosed with HER2+ BC - left breast in 2007 at age 50yrs. 26mm Grade 2 IDC with 1/7 nodes positive for cancer. ER-, PR- and HER2 3+ positive.I had a partial left mastecomy and axillary node clearance. Had 6 mths of chemo in conjunction with 9 mths Herceptin. I didn't have the full course of Herceptin as it caused me to have Congestive Heart Failure. I also had radiotherapy for 6 weeks. Following a routine Mamo late last year they discovered a small tumour on my right breast, This week, it was confirmed to be a small ductal carcinoma, no vascular invasion ER+ PR+ HER status inconclusive (they are doing more tests to determine). I just can't comprehend how I can have another primary with a different pathology. Can anyone help, and advise what further treatment, if any,  I may be in for. Cheers