Brief Answer:
check for 
Anaemia.COPD drugs revision.
Detailed Answer:
Hello there,
Welcome to Healthcare magic,
Nice to meet you here,
As you are on anti-platelet drugs, 
aspirin and 
clopidogrel [plavix] ,it prevents the normal clotting mechanism and resulting prolonged bleeding from minor scratches and wound.
Yes, thin blood with low platelet cause shortening of breath, as they area produced in 
bone marrow, along with RBCs, it usually associated with low red blood cells.
Resulting, inability to carry enough 
oxygen resulting difficult breathing even for a short distance of walk.
So,check for anaemia and get treated accordingly.
I too want you to check for your COPD [chronic obstructive pulmonary disease] and its level of damage to lungs, as it is the most common cause of breathlessness. Advising for a revision of COPD drugs if you got tolerance to already using drugs from your treating physician.
Hope helped you,
Take care. 
Dr.surendiran.g