Firstly, welcome to the forum.
Congratulations on your singing - you'll be pleased to hear that you don't sound at all like someone singing a pop song with a British accent! As you know British pop artists sing in what would be generally called an "American" style, so to me that is what you sound like.
Our American members will need to comment on whether you sound American to them.
I've listened to the song a few times and there are just a few words which, even sung in an pop style, seem to stand out as not quite right. They sound like they are pronounced with a slightly foreign accent. There aren't that many and, I think, if you can concentrate on tightening up pronunciation of these words, it will help improve things:
1. "The" often slips into sounding like "duh"
2. "They" often slips into sounding like "day"
3. "Sleeping" sounds a bit like "slippin" rather than "sleepin'"
4. "Match" sounds like "Murch"
5. "Up" sounds a bit like "ap"
6. "Waking" sounds like "Weking"
As you can see, these are small comments. I only wish I could sing and play the guitar like you can!
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