Sex help.

So I need some advice/help.

When my partner and I first started having sex it was great, amazing and everything mind blowing but lately I can’t seem to get wet. I’m turned on my nothing happens downstairs and we have to use lube. It’s getting beyond frustrating I just want to know if it’s normal to go through this sort of thing.

Just so you know I’m only 21 so I know it’s not menopause 😫