Gambling is a thing you spend money on for entertainment. The moment it becomes a way to make money, or a way to recover money, it has stopped working and the maths has not changed in your favour.
Signs worth stopping for. Staking more than you decided to. Increasing a stake to recover a loss. Playing with money committed to something else, or borrowing to play. Being vague with people close to you about how much you play. Feeling agitated when you try to stop. One of those is enough to justify a break.
Help, now. The National Council on Problem Gambling operates a free confidential helpline 24 hours a day: 1-800-GAMBLER. You can text 800GAM to 53342 or use the chat service at ncpgambling.org. Gamblers Anonymous meets in every state and online.
Tools that work. Set deposit limits, loss limits, session reminders and a cooling-off period when you open an account — while you are calm, not later. Device-level blockers such as Gamban and BetBlocker are more reliable than willpower because they do not negotiate.
One point specific to unlicensed sites. Because these producers sit outside US state licensing, their self-exclusion tools are not connected to any state register. Excluding yourself at one does nothing at the other fourteen. If you need to stop, block at the device rather than trusting an operator's own switch.
If it is someone else. Gam-Anon supports people affected by another person's gambling. It is not your job to fix it and you should not be carrying it alone.