What should I do about the frequent incidence of absentmindedness and doubt regarding the number of prostrations (sujood) and cycles (rak'ahs) during prayer? Is it permissible to interrupt the prayer because of this? And when should the prostration of forgetfulness (sujood al-sahw) be performed before the salām and when should it be performed after it?

If the doubt is daily and continuous (an overwhelming doubt), it is permissible to build upon the greater number. So, if you doubt whether you are in the first or second prostration, you may consider it the second. If you doubt whether you performed one prostration or two, you may consider that you performed two prostrations. In this case, the prostration of forgetfulness (sujud al-sahw) is not obligatory.

However, if the doubt is not continuous, and nothing is preponderant in your mind, then you must dismiss the doubt and build upon certainty (the lesser number). So, you consider that you performed only one prostration, then you sit up, then perform the second prostration, then perform the prostration of forgetfulness before the salaam.

If it preponderates in your mind that it is the second prostration, then you may consider it as such, and perform the prostration of forgetfulness after the salaam.

Interrupting the prayer due to frequent doubts is not correct. Rather, one must follow the legal rulings for forgetfulness. If the worshiper doubts the number of rak'ahs and nothing is preponderant in his mind, he builds upon the lesser number and performs the prostration of forgetfulness before the salaam. However, if a certain number preponderates in his mind, he builds upon it and performs the prostration of forgetfulness after the salaam.