Hey Kira,
Firstly I'd like to say don't worry about not realising it's a dream, it's completely normal to miss out on massive dream signs, it's simply because you were not aware enough at the time.

Is it strange that out of nowhere, I had a complete change in dream content and quality? My dreams are more lucid now too.
No that's completely normal, usually I don't realise though because when I'm not lucid I don't tend to take notice of change, more the plot.

Oh and, has anyone ever had that feedback loop in their dreams? Anyone ever keep waking up in their dreamss?
What your describing is a false awakening, it's where you believe you wake up, resume waking life (not for long usually) and then wake up, it's quite a good way to become lucid, I've become lucid from False Awakenings quite alot just by observing differences to an already familiar site.

I don't think you are becoming 'more' lucid, to be lucid is to realise you are dreaming, I think you are describing how concious you are/how much control you have of the dream, if you aware that you are dreaming it is a lucid dream.

Hope that helped