Hi–
Your post caught my eye and my heart. As a former Protestant with an assurance of true fellowship with Christ–now a Catholic for almost two years–I think I understand how you feel. Some of the issues you identify have been troublesome for me, as well, but some things have been resolved for me as I believed in faith (I believe, help Thou my unbelief!) and then found peace.
Most troublesome for me, too, was the insistence on this and other sub-forums by some that Protestants cannot be saved. I was dumbstruck by it–felt tricked, somehow, but motivated to find out if the Church truly teaches this. The catechism clearly teaches that visible and invisible graces are evident in “our separated brethren” (Protestants) and that the children of the Catholic Church are happy to call them brothers.
The fact that the Catholic Church acknowledges only ONE baptism and that any Christian baptized in the name of the Father, of the Son and of the Holy Spirit is part of the Body of Christ…should suffice that such Christians have access to Heaven.
What we believe is that we have the ‘fullness of the faith’ and that we keep witness in the world of the entire Christian truth. Just as others have said. Even if someone denies the Catholic Church, it is through it that they are saved, when the person repents of sins and seeks God.
That is God’s Plan. Just as no one can change that the original covenant between God and humanity was with the Jews. And that it is valid for all humanity, whether anyone likes it or believes it …or not.
…
This matter has been satisfied for me, though the learning process was painful because of some of the harshness demonstrated in some posts. I am glad I went through it, though, because I learned a lot.
I am a cradle Catholic and those posts hurt me just as much!

I don’t know if that helps in any way. All of us are ‘on a learning curve’ and are God’s ‘works in progress’…but the Mother Church and our Mother Mary will get us there safely!
I hope this helps a little. I am still learning and sometimes doubt my decision to come into the Church, but I find that the daily prayers and sacraments quiet my doubt and give me strength to live the faith daily. He is faithful to me, even when I doubt. I will pray for you.