HERCEPTIN Side Effects

I had my first treatment with Hercpetin yesterday and had a serious side effect. Blood Pressure dropped, Oxygen level dropped was treated with steriod & oxygen. Really scary! Herceptin was stopped and I don't know if it will be recommended that I coutinue with prophylactic measures of Benedryl & Steriods or not. I don't even know if I should attempt it agein. I am 67 years with stage 1 invasive Ductal carcinoma with no lymph node involvement. I am ER positive, PR Negative and Her2 Positive. It is a difficult to know what I should do next. I have had 4 treatments of AC + Cytoxin and am currently on Arimidex. Hopefully, that will keep the cancer from returning, but Herceptin was recommended. Any ideas!