Racing heartbeat ringing in ears

I hope someone can help me. I am fairly new to cpap and have struggled learning to use the machine and mask. It started off promising but went downhill. I have gotten the hang of the mask etc but For some unexplained reason I can only sleep an hour or an hour and a half. At that point I have sudden wake ups that include a racing heart and loud ringing in the ears. The mask is on tight and I’m doing fine right up to the wake up. The ringing can stay for a day or two before I get a break.
If I’m lucky I’ll go back to sleep three or four times repeating some variation of this unpleasant cycle. I use Afrin sparingly or sometimes an antihistamine to keep my nose clear. I have a resmed air sense 11. Pressure 5-15. My apnea count is generally low or zero. It’s impossible to tell what causes the wake up but often I feel like I’m in dream state. I’m hoping someone has experienced this or know someone who has.

Hi- you sound like a perfect candidate to post Oscar results here for experts' interpretation. Tinnitus is not a normal reaction to Cpap. What were your test results? Antihistamines can keep you awake and Afrin can end up addictive. Plus overtightening can even cause new micro leaks etc. Post Oscar according to directions re which graphs, etc. and leave out the calendar... do it all on Imgur.com and put a link in this thread (forum's attachmts are full up right now).