For Last 10 Days I Felt *not Right*. Weakness And

for last 10 days I felt *not right*. weakness and a racing heart coming in waves... dizziness also part. went to doctor, did and EKG and Echo gram, EKG was good, echo gram no results yet. Also did blood test. Doctor gave me anxiety medicine which I took the first night, but it knocked me out and everything still the same. Now I noticed when I stay up longer or walk up the stairs it gets worse. I'm scared but think i may be over reacting.