Your history sounds like genetic hair loss but your photos do not support it. Blonde hair has very low color contrast with the skin so a blonde man can lose over 80% of his hair and often not show it because of the color contrast issue. If you can find a doctor with a HAIRCHECK instrument, you can find out with certainty if you are losing hair. Here are some examples if people similar to you: https://baldingblog.com/2017/01/10/value-haircheck-bulk-measurements-two-patients-seen-today/