Been there done it lad, best advice is only have one online casino and put a limit on it , or 2 if you want different slots etc but half the limit on each.
works for me , and only for slots no table games etc as they can be over in seconds.
if you are a gambler you will always want a punt, but keep the online sensible and you will feel 10x better about yourself.
i put £50 into lotto land on payday and play golden fish tank, bonus or bust. Tbh ive had mixed luck doing that but at least on payday can afford to lose it and then i use the other £50 in the other casino throughout the month when i fancy a bash, works for me lad.