 In academia it's common that we work long hours, we push ourselves over the weekend and we answer emails in crazy hours of the night, all the while reading papers, but it has been proven that your focus and efficiency and accuracy of your work drops when you overwork yourself, so please set a weekly limit and a daily limit to your working hours and try to stick to it. Overworking yourself is not going to make your work better, it'll just make you feel like you're achieving less and putting in more time.