This is observed in many people mainly due to stress in work, weakness and the after effect of some medication. During your pregnancy time and after that during your fever, you might have used some medicines as per the advice of your physician. These medicines will have some effect on your memory and intelligence.
Similarly when you are under pressure also you will have some loss in memory and brain will become a little slow. Pressure will bring the anxiety and that will create many problems like this.
As you become weak physically also, it will also tell upon your memory and intelligence.
You try to spend some time with easy going works without thinking about your problems. You can watch a TV show, you can read a book which you like and you can play with children. That will give some happiness and you will be relieved from pressure.
Eat good food which will give you strength and more stamina. An apple every day will help you. Eat more nutritious food and take proteins.
I suggest the following three general medicines from Ayurveda which will improve your mental power, remembering power and intelligent. There will not have any side effects.
Chyavanaprasya Lehyam: T It is like a soft solid. You can take a small quantity of it (Around 5 Grams) and eat it in the morning.
Saraswathi Taylam: This is an oil made from a special leaf. Daily you apply it to your hair. Mainly on the head.
Saraswathi Lehyam: This is also a soft solid. Around 5 grams of this, you can take in the morning and evening.
Your memory and intelligence will increase.
Try to avoid more work and have a plan of work and follow the plan. Don't get overburdened.