If it sounds right - it probably is. Certain leads need two takes stacked on top one another. Never overthink your work. If your vocals sounds right with the drums alone - take a wild guess what could be your problem . . .
Compare you vocals against each instrument. If you bring a riff in that throws your lead out, that riff dont belong there. Same goes for every other track. Best practice would be to find the instrument in the project that compliment your vocals. Sometimes you just need to replace the kick, snare, synth or keys with another of the same. Most times its the balance of the song too. So if it doesnt fit on track, but fits while you sing to it check these points.