I Was Prescribed Bisoprolol 2.5mg My Icd Activated 6months Ago

I was prescribed bisoprolol 2.5mg my Icd activated 6months ago and the dosage was increased to 10mg. This made me I'll thus I reduced my dosage to 5mg. My iced activated again last week but I did not tell cardiologist had reduced the dosage thus I reverted back to 10mg this week but it has made me ill again. I don't know what to do