Hi Habs, sorry about all the misery your body is going through, hope your doctor can help!
I have had headache problems ever since I was in kindergarden, and after the past few years of keeping close track of what gives me a headache, I have a couple suggestions of what it might be:
Headache with Leg Pain: Dehydration
Even if you are drinking what seems like a lot of water, medication, a hot environment, or very low humidity can cause you to need extra water. Try drinking at least 64oz of water per day. I have to drink 96oz of water per day whenever the humidity is too low indoors, it's nuts.
Headache with Light Sensitivity: Sinus Headache
If you've had any trouble with allergies, you may be having sinus headaches. Sinus headaches can also be caused by being indoors in over-air-conditioned buildings for long periods of time. As the building air is recirculated repeatedly, it loses its humidity, and absorbs the moisture in your nasal passages and sinuses as you breathe it in, causing dry and painful sinus passages. The sinus passages can increase pain and pressure near the eye area, especially above the eyebrow, and cause light sensitivity in some cases. In addition to keeping hydrated, a saline nose spray can instantly reduce headache pain and light sensitivity that is being caused by dry sinuses.
You may also have swelling in your sinuses that is exacerbated by something such as wearing glasses. The pressure of glasses resting on your cheeks (right on the maxillary sinuses!) or pressing on the sides of your nose may aggravate any existing sinus discomfort and cause an acute sinus headache. If you have headaches that start in the morning and get worse as the day goes on, and you wear glasses, it's very possible that this indicates headaches caused by glasses pressing on your sinuses. Try going without your glasses for the first few hours of the day when you get a day off, and see if you finally don't have a headache, you might be surprised!
Headache with Light AND Sound Sensitivity: Migraine
While there are many things that can cause a migraine, the one thing you can try while waiting to see the doctor is to track which foods you eat and see if any of your foods may be causing a migraine. Check to see if you get a bad headache on days where you eat things like chocolate, caffeine, red wine, sulfites, and monosodium glutamate, as these are the most common migraine-inducing items. Sulfites are used in meat seasonings, so if you are buying any pre-cooked or pre-flavored meat products, chances are that they contain sulfites. It will say so on the ingredients. Monosodium glutamate is a flavoring agent found in everything from cheetos to barbecue sauce to salad dressing, found in virtually all soups, and in pretty much all canned and boxed food products and ready-to-cook products. It will say so on the ingredients if a product contains it (they used to be able to call it "spices", it's easier to find now). You may have also developed a food allergy or intolerance to something like fish or eggs that is causing a headache after you eat them, so tracking which foods you eat can be a big help in finding a pattern where eating a certain food makes a really bad headache that day.
There are other causes of migraines, which your doctor should check into as long as you are going to be in the office for a visit. Migraines caused by something other than food can be somewhat relieved with medications, but there isn't really a cure for migraines.
I hope it turns out to be one of the first 2 categories causing your bad headaches, since those aren't really scary and are pretty easy to fix. Migraines would suck but can usually be fixed by avoiding certain foods, and migraine medications can help to make the migraines hurt less. I certainly hope you aren't having any heart problems, but lots of common things could be causing the symptoms you are having, so I hope you are well and that you start having less headaches soon :)