is this normal? Fainting and heart worries

[Shelly15]

So for a couple of months my lungs have felt really tight and I feel like I can't breath, it's like I'm shallow breathing. I went to the doctors who done blood test for iron and thyroid which came back fine and she checked my oxagan levels which was 100% and listened to my lungs which where clear. She said it's properly stress.

I've been near to fainting about 6 times in 2 months like my ears go fizzy my chest goes tight and I feel like I'm just about to pass out I have to lay down so I don't actually pass out.

Today I woke up feeling like I could breath which has been the first time in ages, I was laying down and got up quick ran downstairs then back upstairs and the same thing happend I felt like I was going to faint. Now I've got really bad anxiety that there is something wrong with my heart I always have thuds. why do I keep feeling faint and like I'm just about to actually pass out I feel like it's my heart but I keep trying to tell myself it's proberly where I ran up the stairs to quick but I'm only 27, it happens when I'm in the bath sometimes if I get up out the bath to quick I come so close to fainting!

[zilly84]

Do you have low blood pressure? It could be orthostatic hypotension. I don't believe it's serious and can be treated easily. Even just consuming a bit more salt. I would have my heart checked out if it were me.

Also your could be hyperventilating. You don't have to be breathing fast to do that. Just not taking in enough air. Which is really common in people with anxiety. Try breathing in your nose to the count of 4 and breathing out pursed lips to the count of 6.