Hi Ricky,
I thought you were mostly sharp throughout.
You have a nice enough tone of voice, and you were right often enough for me to think you can sing.
The problem could be as simple as the backing track being too low for you to follow properly, or you could just need some practice.
If you think you struggle a little with melodies, learn to play the tune on a keyboard then practice singing+playing it much slower than the recording.
If you play the melody on the keys and sing at the same time it's often much easier to hear where you're going wrong.
A lot of the time it's just confidence too. Often I'll just hit any note on a keyboard and ask the singer to sing it, but LOUD and PROUD from the get go. No sliding up or down to the note, no fading into it; That's the key.
Usually they start off weak and very self conscious, but after I've made them do it for ten or twenty different notes things really come together.
You kinda get annoyed and just go "AAAAAHHHHH" THERE'S YOUR NOTE! lol.
Hope that doesn't sound too critical.
