Severe Headache,nausea,dizziness,vomiting,pain In Hips And Tailbone
Thanks for your query,
The symptoms mentioned i.e., headache, nausea and dizziness can be caused by multiple medical conditions like Migraine, Ear impairments, Hypertension etc...
As you give a history of increase in the symptoms about an hour after meal, vomiting black/brown slimy substance and glass of water worsens the symptoms, Gastritis too has to be considered as one of the causes.
Vertigo along with headache and nausea can most probably be due to migraine. In this condition, patient will suffer from feeling dizziness anytime before, after or during the headache. There might also be partial loss of vision, loss of coordination, disequilibrium, ringing of ears, and severe nausea.
You also mention about pain in the hip and tail bone. You could have got the hip pain from sitting in awkward positions to relieve the pressure on the coccyx or the hip pain could be caused by bad sitting postures or lifting heavy weight before the coccyx pain then manual treatments such as physiotherapy, osteopathy and chiropractic will often help.
Pain in one region of the body can lead to hypersensitivity of another region due to crosstalk between the nerve fibres. In the case of coccyx pain(tail bone), the whole area of the buttocks and hip region can become hypersensitive because of this effect.
It would be better to get examined by your doctor (general physician) for your headache and an Orthopaedician for your back ache as complete examination and evaluation is required to come to a conclusion and need to treat accordingly.
Hope my answer is informative and adequate, I am available for follow up should you have anymore concerns.