Can you be a problem gambler if you don't gamble every day of the week?

Yes. It's not necessarily how often the behavior occurs, it's what happens when it does. Is the behavior having negative consequences to the gambler or their loved ones? This would be an indication there is a problem.
Talk to counselor. If you gamble money you shouldn't be gambling, if you cannot keep to limits you set yourself, if you throw good money after bad, then there is a gambling problem. Early along, many people with gambling dependency only may do it once a week or less, but like alcohol and drugs, it generally grows more frequent and more severe. If you are wondering if you have a problem, you may well have one.