How do you know what is a side effect and what is nothing much?

@LibbyA I'm on anastrazole and when I first started on it I got some terrible dizzy spells. I was also, like you, very busy at the time , I'd not long finished radiation, we were getting ready to travel to visit our son in Canada and I wanted to apply 3 x 25kg of dynamic lifter on my garden beds in time for spring growth , which was a lot of shovelling and bending up and down, as well as trying to do many other jobs. Looking back , I was doing too much . I thought I could do it all but the dizzy spells were nauseating.  Try and take it easy and look after yourself.  Also, check with your onc . 
Take care xx