Balancing work and playtime

So, for the last three weeks, have been trying to make my son understand why Mummy must work. Last night, the topic came up again as I iron my clothes for the following day. "Mummy don't go to work" he said,giving me his usual sad look as if saying, I miss you so much. That sentence always breaks my heart and a sense of guilt consumes me. But do I have a choice, can I abandon work and how do I then take care of him.
I sat down with him, telling him Mummy needs to work to get money to buy milk, Story books and soccer balls and boots for him; hoping that his love for these would make him abandon the Idea.It was only for the night. This morning, he begged again not to go to work, I tried to explain why mummy must work, only for him to say,"I don't want money," I don't want a ball" Mummy don't go to work."
I was lost for words. Decided to ignore the fact that I was already running late for work and so I sat down and watched Tom and Jerry with him for about 10 minutes. We had breakfast together and then left for work. But can I afford to go to work late everyday, I guess its a dilemma I need to face every single day as a single mum.