I seem 2 drop a lot more hair b4 my menses. Is it normal n is there anyway 2 prevent? I'm 39 n worried my hair may not grow back fast enuf 2 replace

Telogen effluvium. This happens to some women who have a hair loss condition called telogen effluvium. This type of hair loss causes excessive shedding. It is not uncommon for women with this condition to notice more shedding before their menstrual cycle.
Hair loss. It is not that surprising that you would lose more hair around the time of your menses since the hormone levels are fluctuating abruptly. I have never seen anyone lose enough hair this way to be a problem. Stress can also produce the same phenomenon. Hair is very resilient and tends to recover on its own except for very rare autoimmune conditions. No treatment required if no bald patches.