I am a 17 year old female and for about 2 weeks I've constantly had head pressure and felt lightheaded. I've also had heart palpitations where I am aware of my heartbeat, but my heart is not racing. Trips to the doctor and ER have shown that I have a slightly slower heartrate, usually in the 50s. I've been to the ER a few times but the tests came back normal (EKG was normal, CT scan was normal, blood pressure was normal, etc) so they dismissed it as anxiety/stress. I know this is not the case because even when I am not stressed out during the day, I still have these symptoms.

My symptoms seem to shift throughout the day, but like I said, I constantly have this feeling of lightheadedness and head pressure. Sometimes I even get the feeling in my head that feels like when your foot falls asleep, but it goes away... During the day I feel like I just want to sleep, since this is making me feel fatigued... I can function (for example I can get up and walk) but this feeling won't go away.

I'm not sure if these symptoms are related, but lately I've been having dull pains in the back of my shoulder, neck, sides, abdomen, but they're dull and not excruciating. Also, my stool has been dark lately (I wouldn't call it black like tar) so I'm not sure if this has something to do with internal bleeding? I've been drinking V8 juice lately so I'm not sure if that's causing it...

Finally, I remember that a doctor told me about a year ago that I had a "leaky" valve in my heart, but he dismissed it as being nothing at the time since it was a small issue and wasn't causing me these symptoms I am now having.

I've looked online and the closest thing I can guess is that it's MVP? However I am not sure of my condition at all right now and I'm very scared. I want to go to the ER again, but that would stress my parents out, cost more money, and the tests would come back the same, I fear. Has anyone had these symptoms, or know what it could possibly be?