So sorry you've had this side effect from your chemo @ddon
There must be some way of contacting your Onc before your next treatment - even if it is to see a different onc for a 2nd opinion. Can you contact your closest hospital to see who is 'on call'?
My mantra has always been IF IN DOUBT, GET CHECKED OUT - so if you are still worried about this (and I can see why!) go to Emergency and get it all documented so there is a paper trail.
My husband developed a heart condition following his chemo 10 years ago.
I put up a post about it a while back - tho I don't think any happened during treatment other than @Brenda5 - but hers was from AIs.
https://onlinenetwork.bcna.org.au/discussion/19592/cardiomyopathy-and-chemo-a-serious-condition-to-be-aware-of/p1All the best - and I hope it settles down for you asap . xx