It is entirely possible that your tooth pain is causing your headaches. When a tooth becomes inflamed, the nerve endings that pick up the inflammation the tooth may also cause pain to be relayed over other parts of the head. For this reason it is very common for people with bad tooth cavities to complain of more generalized infection.
However, if you feel like the pain is getting worse, that is something you need to get checked out. You may want to go see your primary care doctor
while you are saving up to have a dentist
repair the tooth. I say this because sometimes tooth cavities can progress to serious tooth infections. If these infections are not detected and are left untreated, then can lead to large pus pockets and even to infections that spread to other parts of the body and to the blood stream.
Your primary care doctor can take a look at the tooth and perform a general checkup as well to make sure things are not getting out of control. Make sure to mention to them exactly where the pain is and whether you have any other concerning symptoms, especially swelling or fever