You are still recovering from a fairly hefty op to be honest. Could you have been overdoing it a bit too much?
Is either of your calves swollen or hot to the touch? Is it in both legs or just one?
If you can, maybe have a rest day or two, loads of water, maybe get some floridax into you and see how you feel then. If still not right I think you should go see your gp.
If one of your calves is swollen or hot to the touch you need to call the MYA emergency number they gave you to discuss as soon as possible.
Feel better soon lovely. X