Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.
They couldn't find anything wrong with me (oxygen normal, INR testing at 2.6) but when talking with my doctor, we discovered that my symptoms had come on about the same time we had steam-cleaned our carpets. Turned out my super-sensitive lungs were having an allergic reaction of sorts to the chemicals we used. We upped my asthma medications and spent some time airing out the house better and I've felt a lot better.
I mean, definitely follow-up with your regular doc on the PH, but also think outside the box as to whether there are any other things that might have changed in the last two weeks that could be causing the SOB and etc.
Hope you get it all figured out soon!
http://www.phassociation.org/ has some great information is this is what you are potentially facing