Having a hard time working 5 days a week..

Am I the only one having a hard time holding down my 40hr week job? It feels so hard to make it through some of these days that I lay down whenever I get the chance and my boss was not happy when I told her I was laying down on my break... She said it's not normal for me to be this exhausted.. But I clean house and caregive and nanny for this family and do all the shopping etc.. I feel like it's a lot. I'm feeling anxious and want to just quit but I'm not sure because we need the income... Any advice or suggestions are greatly appreciated :)