Post covid. Feel anxious. please help!

My mother age 50 had covid 4 months ago and she was admitted to hospital for 10 days as her spo2 drop to 80.. since 1 month she sometimes have anxiety without any reason as she don't know why but suddenly start saying "ghabrahat jaisa lagra hai" and so we take her to doctor and doctor gave anxiety tablet and 15 days she took that medicine but after stopping these medicines she again suddenly start saying ghabrahat jaisa lagra hai and it stop automatically after few hours. She doesn't eat properly said don't feel like eating now , and have weakness , done all the test all are normal like cbc and diabetes ( she is not diabetic patients) , d dimer everything is normal it's just anxiety issue for no reason .. please tell us what can be the reason. As she says she is not thinking bad or anything and nothing is in her mind it start suddenly and feel anxious ... Please help