Forgetting how many rakat I have prayed

Assalam alaykum I tend to have issues with memory and concentration, so during namaz I am always forgetting how many rakat I have prayed. and I am always praying more rakat than I need to. I have taken a video of me while praying to make sure if I prayed right or not, and I always pray the correct amount of rakat. But when I am praying, I get waswasah and end up praying extra rakat just to make sure that my prayer is valid, and so for example I would pray 5 rakat for zuhr. Deep down I know that I am praying right but I am always getting wasasah that I haven't prayed enough rakat, so for the past year or so I have been praying extra just in case. Please help.