I had terrible headaches from about week 13-16 or 17, I think. I could barely lift my head up some days. Midwife just said to drink more water, even though I was drinking a minimum of 3 litres a day. I didn't want to take paracetamol all day every day so I saved it for when I really needed or wanted to get up and do something.
I even took time off work for it because some days all I could do was lie still with my eyes shut. I put it down to the shift in hormones as it came just as my nausea went.