Now suppose I have some urine or some drops of urine on my cloth. But I do not know it and am not aware of it. Now, I go and perform my salat. Now, will my salah be ok? Or does it become qada?
If the person who prayers, doesn’t know that his/her clothes is Najis, and after the Salah figure it out that it was Najis, his/her Salah is considered as a correct Salah (prayer), but it is better to do it again in accordance with recommended precaution. Accordingly it seems that your prayers are true. For further info. I suggest you to read the reference as well.