My crisis of confidence over my vocals has lasted decades, so welcome to the club. I agree with pompeyjazz your vocals are improving.
I don't know how much consideration you give to which syllables/words to stress. To my ears some important words in the lyrics seemed to be quieter than they should be and tended to lose their impact. At least for me. Maybe you should consider writing out the words and then underlining which words you think are important. When you sing the song make them a little louder, or the other words a little softer. You should try and hit the strong words on the beat to underline their importance.
You may find putting the emphasis in the wrong place or on the wrong word interesting. Sometimes getting something so wrong teaches you more than getting it right. If you film it and play it back it might make you smile or even laugh out loud. It'd take a brave man to show that to the world though
Good luck.
How often do you sing at Service Station?
Keith