Breathlessness, EF and Mild PAH. 330.

I suffer from sinus tachycardia for which I take metoprolol and olimsartan ( my BP without it used to be around 140/90-95). I had my 2 D echo done on 5th May 2023 with EF 60% and mild PAH 31 mm Hg. I have been told mild PAH is no problem. But since yesterday morning I started having bouts of breathlessness even while sitting ( before that I had no breathlessness). Though oxygen levels at rest are still intact 97-99. I felt very anxious about my deteriorating PAH as breathlessness is main symptoms of it. So I went for 2D Echo again I was told I have same mild PAH of 31 mm but I looked at the report my EF fraction drops to 56% to 60% in just over month. I feel very afraid whether Is it going towards heart failure. I also had Chest X ray and spirometery today which were normal but IGE allergy test was 330.