Hair loss and abnormal growth pattern

Patient: For about 6 years my hair has been falling out increasingly to the point where my hair is noticeably thinner when I tie it up and my hairline has receded. In addition, the individuals hairs themselves seem to be growing out thinner than before. At home and at work, everywhere I look there’s always some hair that’s fallen throughout the day. I had a blood test but my doctor didn’t mention anything abnormal. My hair grows pretty quickly but I noticed that even some of my armpit hair hasn’t grown out three weeks after they’ve been shaved. Some of the hairs are just small stubbles. (I know it sounds strange, but it seems out of the norm since they generally grow out in a day for me). What could be the cause of the excessive hair loss and abnormal pattern of growth and should I seek a second opinion from another doctor?

Symptoms: Thinning hair