Immigrants have about as much correlation with poor people as a cloudy sky has with flooding.
You're wrong about the immigrant thing. If you add a third again as many poor people to your population your statistics are gonna show a lot of poor people.
If you look at the poverty statistics, you've had an enormous increase in poverty and your average wage is much lower. But that's just... math.
Also, those people will push down wages on the lower end. Wages are a function of supply and demand. When you add a whole bunch of people to the supply without increasing demand, the clearing price will be lower just like the price of cars would drop if you doubled production and dumped them on the market. If you're a native born person you're not going to get a raise for a long, long time.
If you really believe suicides are in part driven by income inequality, you can't pretend immigration isn't part of the problem.
Immigrants and their children now make up more than 25% of the US population. How many poor people can you expect an economy to absorb before wages drop on the low end?