Overdose of Mesacol OD (1. 2 gms)

I accidently took two pills of mesacol OD after dinner. I took one pill just at dinner table and took another one forgetting that I had already taken one, after some time. Should I be worried ? Also during regular medication of mesacol OD my first urine in the morning is quite dark. I know it is due to the medication because the problem went away on stopping the medication. Don't worry I am on regular course of medication and will not stop my medication. On drinking more water at night, my sleep gets disturbed as I wake up to go bathroom once or twice. I take mesacol OD one tablet thrice a day. I do not take any other supplement and instead try to eat a well balanced meal and regular serving of fruits. Please advice.