When I was 11 years old I guess I doubted Islam as i heard that Islam allows slavery and orders to execute the apostates etc. at that time I went so crazy that I started flipping coins for example I thought that if it lands heads Islam is the true religion and I tails Christianity is I asked god to show me a sign at that time I did not kin what shirk was and I got satanic whispers which led me too this but I always supported Islam and kept telling myself that there is a reason . When I flipped the coin I said o Allah I know Islam is the true religion please show me a sign but then I said Christian god if your religion is true May it land tails. After Lala that I realized that Islam is the truth and I became a Muslim again as I began to pray but now I'm 13 years old and I fear that I committed shirk that time as now I learned about shirk but when I flipped the coin I only said so e word I never believed that the Christian god is real I just said those word as shay tan misguided me I did not pray or worship the god or anything but I think I invoked him which is shirk I just want to know is that invoking without actually believing is it shirk I can't continue with my life anymore as I am really scared and I can't leave this sin behind me I think about it every second of my life almost I can't continue with my life please tell me if this is shirk.
I understand how you feel, many times i get evil thoughts that cross my head, to the point where at times i used to cry myself to sleep from regret. There is nothing you can do but move on. In every duah you make, pray that Allah SWT forgives you, and thats all any of us can do. Dont put yourself through depression for something that has already happened, as you may have been unaware that what you were doing was wrong at that time, but all you can do now is be the best muslim you can possibly be. Also remember that everything comes down to your intentions. All i can say is try your hardest to be the best person you can be for your religion, and whenever you stand up for prayer or open your hands for duah, always have hope that Allah will forgive you and fear that He wont. whatever act of worship you do, do it from your heart, and remember that even a smile is a good deed :) Whenever you feel yourself going astray seek refuge from Allah SWT from the devil, and just pray that Allah SWT forgives you
may Allah SWT forgive us all for our sins,and grant us Firdaws Al-A'laa. amen