Hi I Am Taking Morphine Sulphate 30mg Slow Ewlwase Capsuals

Hi I am taking morphine sulphate 30mg slow ewlwase capsuals for a shattered knee-cap which has been operated upon 6 times now and they seem to have done as best they could for now and now o n360mg twice a day slow release tablets. I realise that this is a lot and have been on them for 3 months now. I am worried as I went away for three days withuot my tablets and had what I think may have been withdrawals. Could this be the case and if so whay should I do as if am without them I am a lot of pain?