When I wanted to lose weight this is what I did:
I worked out how many calories on average I was eating a day over the course of a week. This was my starting point. I wrote it down in a notepad.
I then decided to deduct 500 calories from it each day. So that was cutting out something like a kitkat and a sandwich. Or a kitkat and a calorific drink.
So I had a deficit each week of 3500 to lose 1lb. But you can tailor this however you want, I've done it at points with a deficit of 1000 a day which led to very fast weight loss.
On this, I was hungry, I didn't sleep that well and I was grumpy and emotionally wrecked but it worked.
I did no exercise. For me this was the key - exercise made me hungry and eat more.
I also paid attention to the calories on packets. Eg, a meal deal. You can make one of a bottle of water, some light crisps like French Fries and a 250 calorie prawn and light bread sandwich, which adds up to about 350 calories total. Or you can make one out of a sugary drink, calorie heavy crisps and a BLT or whatever and you're looking at more like 600-800 calories for one meal.
I also cut out all alcohol and any drinks that weren't water or diet drinks. So zero calories coming in from fluid, apart from special occasions. That made a big difference.
The weight fell off really fast.
OP I've got to warn you. If you do a drastic diet you will feel awful. But I think you know this, and you feel so bad anyway you want to take the risk. Good luck.
I'd say make sure you space you food out.