Last Tuesday I Had An Episode At Work Where I

Last Tuesday I had an episode at work where I thought I was going to faint. Happened again Thursday so I went to the ER. They kept me for 2 days. Had Mri, CT SCAN , blood tests, etc. Discharged with severe sinusitis, and tingling of hands and feet and blood pressure drops when I stand up. I'm on antibiotics and I'm still congested and having these feelings that I'm going to pass out several times an hour. Any thoughts?