What’s wrong with me?

Just trying to see if anyone has experienced any of this and know what’s going on! Or have had similar. I’ll be going to the doctors but just curious! A few weeks ago I thought I was going to pass out. I laid down which helped quite a bit. But ever since I’ve just felt “off”. Sometimes I’ll start feeling weird. Almost like nervous or pit in my stomach. My chest will feel heavy and it kind of feels hard to breathe. Sometimes my hands and arms feel heavy or numb and I get lightheaded. Is it stress? My blood pressure? Anxiety? Just curious as to why this could be happening.