Well, you sing about like I do, but that's O.K. because your at least singing and making the effort. The guitar playing is good but to far up front in the song, the vocals should always stand out front where singing is going to be in a song. Drums will be heard better when you drop the guitar back a bit and bring up the vocals a tad, just so the are up front. It is a good song that just needs a touch here and there. You could hit it with a resonant filter to see how that effects everything. Mastering is all about fine tuning each track individually before mastering the over all mix. Here are a couple of pointers to consider, maximize, equalizer, dynamics, stereo imaging, post equalizer, harmonics exciter, reverb and dithering. These aren't all necessarily used on each track but each track has to work in the over all spectrum of a completed song. Hope this will be helpful. Sorry about your lost love, but if it brought you to a better place than you were, as stated, then it was all worth it.
Peace be with you. Blessings, John