My prayers don’t feel like prayers and I feel faithless and scared. I feel somewhat ashamed/rejected because of my fear and because I did not take communion.
I've been there too. I have an anxiety disorder and suffer occasional panic attacks (especially in certain situations).
I am on medication, and thankfully it helped with the middle of the night, out of nowhere panic attacks, but I still deal with a certain amount of it, which has become somewhat worse since I moved from Canada to the U.S. a few years ago.
Anyway, long story short, going up for Communion is one of the situations in which I have experienced panic attacks, in front of everyone, so that my legs would shake badly and I couldn't walk very well. There have been times I have avoided going up for Communion because of this, and oh how I have felt so hopeless, and as you said, "faithless", because I had let my fear get the best of me. How I told myself I had failed God and how I cried and begged Him to forgive me.
I cling to the Scriptures that tell us there is no longer any condemnation for those in Christ, and that even when we are "faithless", He abides faithful, and cannot deny Himself.
See, our "flesh" (which wars against the Spirit) will fail. The "inner man, the new creation we are in Christ, as born again believers who have passed from death to life, is entirely without sin, because we have Christ's righteousness.
And He will never leave us or forsake us.
Prayers, and God bless you DeerGlow.