Constant Headache. A days i sleep for!

I have been having regular headache from last two years. Earlier it wasn't so frequent as it is now. It generally happens when I don't eat for a long interval of time or if I could not go to toilet for a long interval of time ( may be for around 1 day or more since I am also suffering from constipation). Earlier I used to face problems whenever I remained out in sunlight for around 1-2 hours or more than this. But now it does not happens so frequent. Whenever i suffer from this headche I generally try to vomit now a days which makes me feel little relaxed. But vomitting happens sometimes and sometimes not. Sometimes the headache becomes so severe that I use to take painkillers. I also have some problems with my digestion system. Whenever I use to eat spicy foods, the next day I suffer from improper excretion problems. I suffer from constipation problems due to improper digestion. I feel the headche is somehow related to my constipation problems. Other than this, now a days I sleep for