Talk to Dermatologist on Weakness And Curl Of My Hairs

my hairs are getting very thin day by day and a little hair fall I've tried alot of products to make it thick but i don't think i can do it by myself and also I don't like curly hairs so i applied hair straightening cream many times in my hairs which makes my hairs straight for almost 2 months i also applied hair keratin treatment from saloon which lasts for 4 months now I'm so worried about my hairs I'm losing it day by day also it is getting thinner please advise me and help me how to make it thick and straight i shall be very thankful to you