What's happening to you is super common and the root cause is almost always the same: without a clear plan, expenses just expand on their own 🌱 Others already mentioned tracking (which is fundamental, don't get me wrong), but there's something people forget: you have to start saving FIRST, not after. It sounds backwards, but it works. When you get paid, before you spend money on anything else, you transfer a fixed percentage to a separate account (it could be 5%, 10%, whatever's possible) and it disappears from sight. You use the rest normally. It's easier to go without something you can't see than to try to save whatever's "left over" at the end of the month, because there's never anything left over.
Besides the tracking thing (yeah, do it because you need to see where the bleeding is), figure out what your biggest money leak is. For a lot of people it's eating out, sleeping subscriptions, or gas/transportation. In my case I discovered I was blowing money on small things I didn't even remember buying. Once you spot that pattern, it's way easier to cut.
Here's the trick nobody really talks about: open an account at a different bank than the one you normally use, without a debit card attached. You transfer your savings there each month and that's it, you don't have the temptation right there. It's psychological but it works so well. In 6 months you can build up a decent emergency fund without it hurting as much 💪