Sub-acute PE possibilities

Greetings all,
In January I threw my 2nd PE.  It is a major PE in that there are multiple emboli in each lung.  Yet in spite of this I do not need O2 on a continual basis.  My first sign of symptoms was when I was taking the garbage out, which tired me out to the point where I had to take a break walking back to the house.  Of course my male ego had me saying "I'm okay" when my wife consistently asked me if I'm okay.  I got to work and found my self tiring to the same level walking in from the parking lot and walking around at work.  After a call to my General Practitioner after hours I was advised to follow up with an appointment.  I then left work and drove myself home, and when I got to the Dr. office my O2 level bottomed out at 86% walking in.  I  was in the hospital for a couple of days.  Genetic tests were normal.  I proceeded to work on improving my lungs.  I swim once a week as my main form of exercise, supplementing it with a recumbant bike during the week.  Pre-PE I was doing 20 minutes easily, post-PE one length tired me to the point where I had to rest briefly before continuing.  So I backed up a step and did walking in the swimming pool for my exercise.  After several weeks I was back up to swimming and matching my pre-PE levels.
2 Weekends ago a friend helped me carry the air conditioner up, and my reaction was normal, being moderately winded.  I was getting winded prior to that picking up the house, but contributed it to normal activity.  Later that day I got in the pool and found myself seriously winded after one length.  I did exactly 4 lengths and quit.  When my wife saw me (sitting down) she said I looked pale.  We called an ambulance and ended up in ER.  Tests for a heart attack were normal.  CT scan (which was sub optimal) did not indicate any new clots, but did not have sufficient resolution for anything more accurate.
This past weekend when I woke up I got out of bed, went to the bathroom and then to the couch.  My O2 was below 90%, and my wife said I looked pale.  Another ambulance ride and I'm in ER again.  Walking around ER my O2 dropped below 90%.  A CT scan was not repeated.   Following up with my PCP his suspicion is I may be having sub-acute PEs, which means I am throwing small clots while on blood thinners.  After some intervention from my PCP I am seeing a pulmonologist at 1:00 PM today.
I am understandably concerned.  Time for some meditation.
 
Mike