If I am in my last rakat, And I finished the sajda And I am in the position of salam so I say ‘Allahou akbar’ and then I doubt if I did 1 or 2 sajda but I dont start the zikr of salam.

Is this invalid the prayer?

Or its ok because I am going to start the zikr of salam?

You should do another sajjda before tashahud.