Hi, welcome to the club!
Congratulations with the changed lifestyle. How long is your commute? Have you biked in every day? Which bike do you have (a picture in the sticky commuter bike pictures thread is most welcome!)?

Regarding the equipment and clothing; there is a lot of good info in the advice for beginners sticky thread. But generally sweating in cotton clothes is unpleasant and jeans are probably the worst biking trousers you can imagine. You probably have some better options in your closets which you could try before spending $ on some bike specific clothes. After all, finding the right gear is a trial-and-error experience.
I also get headaches from sunglasses, but getting bugs, dust and other debris in the eyes can be very dangerous. Finding a pair of glasses that work for you is vital.