HELP!! Scared! MUGA dropped

[Her2Sue]

Please someone tell me I am gonna survive this! Everything is good as far as my cancer being caught! Clear margins, clear nodes! I am having to do Herceptin for the rest of the year. Well I went for treatment today and Onc said my MUGA dropped to 55. NOW I am SCARED!! How do you get past this fear? I am scared I am gonna fall over dead! What does it mean when our MUGA drops? Is the damage repairable? Somebody please advice!!
Thank you
Susan