Exercising after sprained ankle

I sprained my ankle badly at the beginning of December and there is still some swelling as well as soreness in both the ankle and calf. I thought doing some swimming might help rehabilitate the ankle and calf muscles, butt after going today and the ankle is now quite sore. Forgive what may well sound like a stupid question, but should I stop exercising or keep going, i.e. is the pain/discomfort a warning sign to stop?

Thanks