First of all, don't panic. It's okay, with some simple tips and tricks, you can take charge of your hair fall issues. Stressing over this would eventually cause you to lose more hair than normal.
Clean up your diet right away. Eat more vegetables, protein-rich foods, potassium, and magnesium-enriched foods, and drink plenty of water. What goes inside will reflect outside so ensure that you are eating healthily.
Apart from the diet, make sure that you're not using any harsh chemicals on your hair. Using holistic and natural products on your scalp will keep them healthy and free from any issues. For dry scalp and dandruff, consider using a dermatitis shampoo with herbal and botanical complex.
Let me know if this helps! Thanks!