Feeling weak after heavy periods is okay.
If you have heavy periods every month, you may need treatment.
I strongly suggest Homeopathy treatment for you as it is very safe and it will correct hormonal imbalance making your periods normal.
Next Steps
Opt for Homeopathy.
Health Tips
Eat plenty of green leafy vegetables, dates, apple to improve hemoglobin. regular exercise also corrects hormonal imbalances.