Hair loss at crown. Im 18. About stress?

No one in my family has hair loss. I have been having hair loss since 8 months. About 100 strands per day. The hair whorl is opening up and is clearly seen. Hair density on top of my head is also lessening. No receding hairline or temporal hair loss though. I did take acne medication(antibiotics) about 8 months ago. Can it be the cause? However my mother did tell me she was born with few strand herself. Took homeopathic medication and she is now fine. She has no hair loss. I haven't exercised regularly for the past 1 year due to studying. I also ate a lot of Kurkure. Now I have stopped. Can that be an issue? Can weight gain be an issue? I have gained 6 kgs over the past year. I don't style my hair at all apart from using the comb. Can certainly shampoos cause hair loss? I've used Tresemme for the past year. I have stopped that too. I apply coconut oil at least twice a week and take good care. What about stress? I don't want to lose the hair I've got left. This is a real concern for me.