Any other symptoms that dont seem related? Chronic headaches, eye pain, stabbing sensations, ankles and feet hurt, muscle and joint pain that moves around, sensativaties to light, sound, smell? "brain fog", vertigo, fatigue, sometimes feel like you are going to throw up? Sore throat, heart "skips" occasionally, chest pain, and do you have some "good" days and some "bad" days and does it seem cyclical? . Neuropathy in legs or arms? tingling?
maybe a bacterial infection or pregnancy? x
Lightheadedness, juxtaposed with a compensatory high blood pressure, and trembling, is strongly suggestive of both dehydration and either anemia, or a low hematocrit. So square one is to get blood work. The blood pressure reading is not helpful without knowing the heart rate and rhythym. Rather than getting a simple blood sugar you need a test called an hba1c. In the United States, the hba1c test kits can be purchased in a drug store, as well as on the internet. You really need an in-person evaluation by a physician.
That's not very specific. From your profile I see you are a 33-year-old female, possibly overweight. The high blood pressure and joint pain would be from carrying too much weight.
The trembling and light-headedness could be many different things, including diabetes.
Changing your diet to one high in omega 3s, no junk food/fried food, mostly eating vegetables and fruit and lean meats, poultry and fish, trying to avoid grains and prepared foods, and adding Metamucil every day, would turn your health around.
You need to find out about your blood sugar and go on a strict plan of walking every day, increasing the distance and speed as you get healthier. Add light weight workout with a training showing you proper technique and you can change everything and start your body functioning like it ought to.