Welcome to GT.
I am one of those old men you see in the casino. At least I was until last year.
To me it’s quite obvious what your first step should be. Go to that casino, without taking any cash or cards, and ask them to exclude you.
If you’re in UK and it’s one of the big nationwide ones (grosvener or Stanley) they will give you a life time exclusion if you tell them you are a cg. (Compulsive gambler).
Of course doing that won’t stop you gambling, but it will make it a bit harder. You say you’ve been watching the wheel for hours, was that on tv? If so try not to.
Do you consider yourself a CG.? Has your life becme unmanageable because of gambling?
You need to remain focussed on your education, as you know gambling can consume all your thoughts and headspace. You really are gambling with your future.
Can you talk about this to a family member, or someone you trust? If so ask them to look after your money til you go on holiday.
I wish you well, take care.