Dear Friend, would need additional details to evaluate your problem further . However, if you have observed this change recently, then it could be due to some negative thoughts bothering your mind and distracting your concentration. Some time it could also be due to imbalance in your body energies, especially if you have aggravated air energy (called as Vata in Ayurveda), you may experience such memory or recollection issues. You can recover easily, if you follow some recommendations after consultation.
Next Steps
There are natural remedies and supplements available if it's related to body problems. If not, you may need a counseling session to figure out the root cause.
Health Tips
yoga and meditation can help you bring down any unnecessary stress and help to balance your mind.