Is this really normal?

I (f / 25) have been having some symptoms slowly coming on for years now and I finally went to the doctor.

We took bloodsugar measurements in the morning and after eating. We measured my blood pressure and heartrate upon sitting and standing. And we did a blood count. Doctor said, everything seems fine and my symptoms might just be „normal“.

I would like to know whether you think I should get a second opinion? Do you have any idea as to what could be wrong?

My symptoms are:

always thirsty, drinking and peeing >5 L daily /// really bad night sweats /// When I go from sitting/laying to standing I almost always get symptoms: dizziness, vision loss, air hunger, heart palpitations, hearing loss & ringing, tingling arms, loosing muscle tone, arms twitching. I never actually pass out and the symptoms vary in severity. I also get them when I exercise. /// Mornings are really hard for me. My chest feels tight and breathing is exhausting. My muscles are so weak I can barely hold on to anything. I am soo cold. This lasts up to 3 h and is not connected to how much sleep I had. /// very slow bowel movement and frequent bloating /// body temperature frequently around 35 degrees C /// feet get purple upon standing for a longer period of time /// weight loss /// episodes with tremors and cold sweat /// oftentimes seeing stars when turning my head /// heat intolerance