decompresion sickness

Question
3 days ago I was diving in 100' of water with a new dive buddy, who not only had a gauge malfunction, but also sucks a lot of air. To make a long story short, we ended up sharing my air on the way up. This cut our safety break short. Instead of 5 mins @ 15', we sucked my tank dry in about 2 mins. When we got back to the boat I had a pretty bad headache and some nausea. my buddy felt fine. The symptoms only lasted for a couple of hours, I have felt good since. Im not sure if I had decompression sickness or to what extent. Is it safe for me to dive? should I start shallow and see how I feel?

Answer
Hello Jim, Headaches remain a problem for many divers, especially for beginners,(I don't know your level of expertise) as tension and anxiety play a big roll in causing headaches.By what you have told me, it seems that you really sucked up the air. I don't think you had Decomp.sickness per say..(maybe a mild D.C.S.Headache,but without all the symtoms). To me it sounds like your headache was  caused by not breathing properly. Skip-breathing (in order to conserve air) will cause a CO-2 buildup in the body, and will lead to a bad headache, because you are not FULLY exhaling all of the CO-2 from your lungs.A CO-2 toxicity headache is usually caused by Hypoventilation, because the diver does not take Large enough breaths from his/her tank,or does not breath DEEP AND FULLY. Again, there are many causes, that result in Diver headaches, and proof of the exact cause can sometimes be difficult to pinpoint. Here are some other causes:
                 Clinching down hard on your mouthpiece (tension headache)         Inefficient equipment        
                 Mask adjusted to tight.
                 Sinus squeeze(and reverse sinus squeeze)
                 Inadvertant Saltwater inhalation
                 Being Dehydrated(This is a major cause of diver headaches. It is very important to drink lots of water BEFORE and AFTER your Dive)3-4 liters/day....(the day of your dive)
                 Wet-suit too tight around the Neck
             If this was a one time incident Jim, and you have no other health issues, then i would say to you go ahead and continue to dive, but start by doing several NO-DECOMP. dives(but don't cheat on your safety-stop)....and see how you feel after, and hopefully no more equip. malfunctions.I hope i have helped you, and thanks for the question.

                         Gary S.
                 "Plan your dive....Dive your Plan"