Hi, as you mentioned that your mother is on heart and
sugar medications, so first of all you should get your medications checked by your treating doctor because low platelets can be one of the cause of drugs side effect. Also see if your mother is suffering from any viral diseases because it can also cause low platelets.
Next Steps
If everything is normal and no cause is found then you may seek help of hematologist.
Health Tips
Keep watch for any rashes, bleeding from any part of body like gum bleeding, nose bleeding etc. In such cases go to emergency in hospital.