I along with many people I've spoken with, believe rain can affect the way you feel.  It has rained everyday for over two weeks where I live with more predicted thru the weekend into midweek.  Even the French Quarter in New Orleans was flooding yesterday and it's the highest part of that area of the city.

Weather changes mean atmospheric pressure changes.
That alone has an influence on the cardiovascular system, nervous system and behavior.
Weather can cause people to fatigue more quickly, possibly to the point of heat exhaustion or hypothermia.
It is also not good for someone to be outside when temperature are high, then go into a good area.  We all do that in Louisiana just about everyday during Spring, Summer even Fall.  At work, at home, while shopping in and out of stores and the first thing we do when we get into the car on a hot day, is turn the air conditioning wide open.

Did you know that it's a scientific fact that when weather starts to change from good to bad, animals all around the world act strangely. Think the weather's about to go down hill, listen to frogs.  Frogs croak louder and longer when the weather is going to be bad. 

It affects them the same as it affects us humans.

After long periods of rain, sunshine seems to lift the spirits of people and even animals get more playful.

As far back as the 1960s, medical researchers have found, over and over again, that there is a genuine connection between increased pain and cold, wet weather. While the effect is most commonly linked to arthritis sufferers, many have also reported feeling increased pain from nerve disorders, recently healed fractures, migraines, toothaches, corns, and even scars, when the weather was about to change.

No one knows exactly what causes aches and pains to flare up, but the most likely culprit is the drop in atmospheric pressure that occurs right before a storm begins. This shift in air pressure may be enough to dilate the blood vessels in the body, stimulating the nerve endings in sensitive areas, like sore feet, creaky knees, or bad teeth.

Many people in the Acadiana area are feel tired, drained, and one common complaint among many is that their head feels like a bowling ball.  "I just can't pick my head up.  I couldn't get out of bed yesterday" said a resident of Youngsville.

I've included a couple of videos that may help you figure out why your head is stuffy and heavy feeling.

[Via:  Answers.com,.farmersalmanac.com]