I'm getting more and more spooked by algae, seaweed, etc...

hello all, i've been swimming in a lake in upstate NY the last few weeks and I'm finding I get more and more spooked when I see algae, leaves, branches, etc. Any suggestions on how to work on this? I found when I concentrated and counted strokes, I could keep my form and do well. But it didn't last. I'd start to spook myself out again and my form would deteriorate because i keep trying to sight what's ahead of me. How do you deal with the harmless debris you might bump into on your lake or ocean swims? The lake i'm in is relatively clean, though murky. 3-4 feet visibility. I also have a kayaker accompany me. Chris