How did you get Theophylline? Did your doctor give it to you? Pubmed says it "is used to prevent and treat wheezing, shortness of breath, and difficulty breathing caused by asthma, chronic bronchitis, emphysema, and other lung diseases. It relaxes and opens air passages in the lungs, making it easier to breathe." That is NOT a treatment for apnea. Apnea is when your airway actually collapses, or your brain forgets to tell you to breathe. If your doctor gave it to you, I would be alarmed (unless you do have asthma or one of the other conditions for which the medication is indicated) and tell you to go back and question him about it. If you somehow got some yourself, I would be extremely alarmed and tell you go to your doc immediately!
You currently are using one of the best treatments for apnea--the machine. It is not realistic to feel immediately better after only one month of treatment. Read this site for a while and you will see that some people take a very long time to feel a real benefit to the treatment. Very few feel like a million dollars after just one month. For me, it was several months before I realized a real change, and a year before I had all the bugs truly worked out.
If you are having issues adjusting to the machine and the pressure, you would get better responses by posting a new thread with just one topic -- asking about how to adjust the pressure on your ASV so you can fall asleep. Please do people a favor, however, and add your machine type to your profile so people can see it. And if asking about the machine settings, include it in the post as well.
There are also other causes for exhaustion. But you do need to give the machine a longer try, and work with your doctor or DME to make adjustments (one at a time) if you find things aren't working, and give it some time after each adjustment to see if there is a difference. And you need to work with your doctor on your whole health picture, too. You may have other conditions going on that you're not noticing now, but may notice once you get the apnea under better control.
Which leads me to your GERD question.
Has your doctor diagnosed you with GERD, or did you self-diagnose? If self-diagnosed, please do yourself a favor and go to the doc and let them work this out. They need to rule out other possible causes for your symptoms, and, if it is GERD, work out a treatment plan that takes your other conditions and the medications' side effects into account. If it is truly GERD there are many other meds to try, which a doctor can set you up with.
Take this seriously, because it is serious. Lots of people say "it's just GERD," but that's like saying with sleep apnea that you're just tired. It has real, long-term, serious effects if not treated. Do some searching and see for yourself.
I know this is a lot to deal with, but it is you can do it. Hang in there!
DX 7/22/10, started treatment 8/25/10
REMstar S1 Pro C-Flex+ / Swift LT for Her mask, 9/14/10
RemStar S1 Pro DS 550 Auto 3/20/12
Usual pressure 4-8
AHI before CPAP, 26; now .7