... My dear, that's totally understandable
A mother is the most precious person you'll ever have. Nothing I could say may actually fade away the pain of such loss. Neither I will say the tipical things like "she wouldnt want you like this" because, really, they may be true but that helps nothing.
But what I think may help is to remember, not trying to forget nor avoid to think of her. Remember the happy memories you surely made together, and think that she parted taking with herself a life full of joyous experiencies, like having you, and precious moments.
Also, somebody told me once than the most sincere tears are also the deepest. In fact, so deep that they might never find the way to the surface. But that doesn't mean they aren't there.