The main thing to remember is however you are dealing with it is the right way, for you. If you feel that by getting up and going into work, and carrying on as normal is currently the best way to cope, then thats how you should act. However if you feel that at some point you just want to break down, not leave the house for a week, and grieve in another way, then that too is fine.
I think for the time being just let yourself deal with the loss of your mum how best feels right...but should it carry on for too long, for example in 2 months time you feel youre struggling to carry on with every day life, be prepared to accept you may need help, as in proffessional help, just to get over what has to be one of the hardest things for someone to deal with.
Lots of love and hugs being sent your way!