One thing I think should be said is that you can't write music with theory. Theory is great for helping to dissect music and understand it once it's written, but it won't write music for you. Listen to what your playing and decide why it doesn't sound right because of the way it sounds and then decide what will make it sound the way you want. Just assuming that it is the chords your playing or a problem with the key is not the way to do it because music can sound off for a million reasons.

It seems like when you run into a problem you go straight to the chord progression or key and think it has to be a problem with theory. I think the reason you have to keep coming here and asking these questions is because even though you know theory your trying to rely on it way to much and it simply will not help you write music. You need to just listen to what you wrote and make conscious decisions about how to get the sound you want without going to theory. This may be a little difficult at first and you may feel like you have no idea but if you keep trying it and as your ear gets better you will be a much better musician and song writer for it.