We can't afford immigration

I have nothing against foreign immigrants. However I feel like our country is doing pretty badly right now, how can we afford to constantly have people coming in? We already have few jobs and loads of national debt. More immigration just makes our lack of jobs worse. Many of them end up sending their salaries back home anyway, so our economy loses money. Plus they use our social services like welfare and foodstamps, which their country doesn’t have. I think once we fixed our economy, then we can have more immigration, but right now it just doesn’t make any sense.