My (21M) girlfriend (25F) spends too much money, how can I tell her I need to be on a budget?

For context Me(21/M) and my girlfriend(25/F) and I have been dating for about 5 months now. She has always loved to spend a lot of money. Our first few dates I covered the bill but she would rack up a $200 plus bill on drinks, appetizers, an expensive entree, etc. I was fine with that on the first date but I’m a college student and have only a part time job and I can’t afford to be paying for dates like this. It’s not just dinner that she spends a lot either, she wants to go on dates every couple of days. This would be fine if I weren’t dropping $100 plus dollars each time.

I’ve mentioned to her that I’m on a budget and she always says “oh yeah that’s fine I totally understand” and then we’ll do some low cost date and she’ll somehow find a way to spend a ton of money usually on drinks or food. And then I feel like a douche and like I’m not a gentleman because I don’t pay for the food/drinks even though most of the stuff she orders are for her.

How can I get my point across that I’m on a budget and can’t be spending all this money?