Download myfitnesspal and start learning how to use it.
It takes a while to get the hang of it, but even without trying for a weight loss goal you can start to really get an idea of where your calories come from and where your actual nutrition and energy come from.
Losing weight and keeping it off, esp that much, is a process of developing different attitudes and habits that last in your daily life. It takes time. There's no real quick fix, although when you start off you may see results quickly. Those results are momentum and it's extremely difficult to keep that momentum when your body and habits are pulling you back like a rubber band.
Start slow, small changes, maybe a short walk in the evening. Skip one processed snack and substitute something natural & whole like an apple or a chopped carrot or whatever.
There's no real reason why you can't do this, though. It's just time and a certain consistent effort to keep going past what your brain will try to convince you are FAILURES. There is no real failure. Anyone who succeeds at this is someone who "failed" many times before.
Start slow, eat less, do not skip sleep. Do not think that eat less means you cant eat anything anymore, watch your carbs and fatt, do some cardio BUT START SLOW. Build it up.
The other comment which begins with the myfitnesspal app, has some very good advice! Watch and learn!