I want to enjoy my life !

hello, it's 01:29 am, last time I eat was at 09:00 yesterday. I decided to go on a water fast.
I've been on and off with water fasts, I reach day 3 and I give up ... Mostly cz I'm always home where food is at reach or cz I can't concentrate in class...
I'm a 21yo male and I'm used to fasting (I do Ramadan every year).
I can't seem to get the results I want with the regular diets, I end up depressed. I did keto last Ramadan and it was great but I can't stand it ...
My goal isn't specific weight but mosly looking good in the clothes I bought last year but didn't get the chance to wear.
I'm a finance student ans this summer I must do a 2 months internship in a Bank, Hedge fund, Audit cabinet, ... I must wear formal clothes: suit and tie ! I never wore those, always wanted to but I've always been fat but now I have to get my life back cz this is my futur!
To sum up, I'll be updating this post (mainly for me as a journey). My goal like I said before is to fit in my fav clothes. I'm aiming for a 7 days water fast.

I have some questions if someone can anwser me :
- how can I keep the headache off ? That's what bothers me the most since I have to study ...
- I like to walk (10km per day on school days), shouild I stop ?

Thank you!