Persistent Headache. On the sides!

For the past 8 months, I have been experiencing severe headaches involving the front, sides, back of my head and neck. Initially, they lasted for short periods, but they have gradually progressed and now can last almost the entire day. I initially ignored them thinking they were normal tension headaches and took no medication, but the symptoms have progressively increased and new symptoms have appeared. I now experience blurred vision with occasional brief episodes of complete blackening of vision, eye pain and very heavy eyelids, constant muffled hearing with brief episodes of markedly muffled sounds, difficulty retaining information, finding words, getting stuck while speaking and mispronouncing words, excessive fatigue and sleepiness, jaw pain, difficulty rotating my neck, constant pain in both legs with night-time calf/foot cramps, severe hand pain, recurrent constipation, episodes of difficulty breathing, and chest/hand-arm pain. I have also noticed prominent vessels on the sides