Shooting myself in the foot

I've said for some time now, that there's no point in me doing longer days and working weekends. All that happens is my brain switches off and I make mistakes or I get sick. If I try to do the longer hours, I pay for it in just as many hours lost later to inefficiency, mistakes and illness. So, I have these really short deadlines for papers/grants/lecture writing & end up spending all weekend working on the paper. Sunday night I get a sore throat and I've lost 2 days of work with brain capacity falling to about 5% of normal, a desperate desire to sleep and feeling generally like crap. I actually feel a bit better today and the woman in the office across from me says I look terrible and wan. My eyes are very bleary. I really should learn and stop paying attention to people who say I should work the weekend/after hours if something has to be done.