Part of why it's hit the UK so hard was because they made the outwardly reasonable choice to delay second doses. Unfortunately, it turned out to be a poor choice.

If you haven't got around to your second dose, it's not too late to get it. The first dose provides about 60% protection against other strains, but only about 33% against Delta for some reason.

Get your shots. And don't be scared of the horrible side effects; a lot of people don't even get those. I didn't.