Anxiety - stress. Feeling in my brain?

For the past three months, I have been facing health issues. It started with chest pain and stomach discomfort. When I go to bed, I can feel my heartbeat—it sometimes beats very fast, other times slow and hard. I consulted a cardiologist and a general physician. Blood tests, ECG, and Echo were done, and everything came back normal. One morning, I woke up with dizziness and head spinning. The doctor said it was stress-related and prescribed PLACIDA tablets for 15 days. However, when I stopped taking the medicine, the symptoms returned. Now, I experience a strange sensation in my head and find it difficult to concentrate on work. I have started meditation, but I still feel uncomfortable. Can anyone suggest ways to get relief from this weird feeling in my brain?