I'm a leftie too, diagnosed Oct, surgery Nov and Dec, first chemo Jan, and about to have my 2nd chemo the end of this week.
You can tell or not tell whoever you like but if they are sorts likely to be dropping in to your place while you are on chemo you might like to limit them to the times when your white cells are not at their lowest, about 10 days after each dose. You need to stay healthy and not catch any bugs going around.
I have day by day reports on my blog how my chemo reacted with me. I had not really any idea and nor do each of us until its given to our bodies. So far so good for me. :)