I am the lone freediver in my area, I have began freediving for abalone in northern California 40 years ago and I am 55 years old now. In recent years I have been working on upgrading my freediving abilities with help from books like "The Freediving Manual / Underwater on a Single Breath". I swim in the pool for cardio, do breathing excercises, dynamic apnea in the pool and practice diving in the bay. Since I am often on my own I am very conservative and do not push my limits much without someone around. On the 14th I was practice diving to 50 feet and the next morning during breathing excercises I noticed a small amout of blood in my phlegm. Two days later I was spearfishing to 40 or 45 feet and the next morning I say what might have been blood as well. A physical and chest xray since showes no obvious pathology or injury but it might be lung sqeeze. Any thoughts or advice?