Hi there. I've been a hairstylist for almost 20 years. Of course there are many reasons for hair loss, medication, thyroid, low iron, genetics... Stress is a bad one. But hopefully this will be a positive reminder for you. An average human can shed 100 and even up to 500 hairs a day NORMALLY. Depending on the time of year especially, and as a woman, depending on the time of the month. If you have long hair, each hair shed can actually appear to be more than just one if it's all scrunched up on the shower floor or in a brush.
Also, your hair line is completely unique to you. Comparing yours with another woman's will have no affect. Also, not washing your hair will create a build up on your scalp which causes weight at the root of the hair and can cause it to fall out sooner than normal. Shampoo gently with a good sulfate free, and paraben free shampoo, and comb through gently afterwards. The less you wash the more hair you'll see come out when you do... that is normal
I'm sorry that you are experiencing this fear. Please be reassured that what you're experiencing is probably just normal shedding as it doesn't sound like you have apparent thinning. <3