Does anyone have any ideas about what could be causing my symptoms

[hazelhorse]

I am normally a very fit and well 57 year old capable of working hard in a physical job.  Over the winter (our quiet work period) I had four chest infections (never had one before) I have also developed gastric reflux and huge abdominal bloating and continual pelvic pain.  I also have fluid retention in arms and legs with dry red skin.  I have worsening fatigue and now cannot walk 50metres up a gentle gradient without stopping for breath, feeling dizzy and faint and having lactic acid build up in leg and buttock muscles.  All blood tests have come back normal apart from low Hb which I have had all my adult life at least.  Scan shows intestines full of gas but nothing else.  Coeliac test negative.  Chest X-ray clear.  
GP is at a loss and says try over the counter IBS medication for the bloating ( prescription of mebeverine didn't help)  Her only other suggestion is that it is anxiety or stress related.  I have lived a fairly stressful life for the past 30 years with no physical problems, so is this possible?