All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It seems that you are somewhat affected with whispers, so we advise you to repel them, ignore them, and not pay any attention to them, and behave normally.
You should know the Sharee’ah ruling and act according to it, and then ignore any whispers that you may have.
None of this is Shirk and you are not doing any showing off, Allah willing.
As regards Al-Faatihah, then the scholars differed in opinion whether or not it is an obligation for the person led in prayer to recite it. You may act according to the view of any scholar whom you trust.
The view that we adopt is that it is an obligation on the person led in prayer, and that he may delay Rukoo' in order to complete its recitation even if the Imaam goes to the Rukoo’ position. However, you have to recite in a normal manner without overburdening yourself and without having whispers.
Also, between the two prostrations, you must say: "Rabbigh-fir-li" (O Allah! Forgive me) at least once, and then you follow the Imaam.
If you do this, you will not be delayed from him. The same thing applies to the Rukoo’ (bowing down) and Sujood (prostration), if you say one obligatory Tasbeeh, then you will be able to follow the Imaam and you will not stay behind him.
Allah knows best.