Hi, I'm a 32 year old female and I'm hoping someone has some more ideas if what could be going in with me

last week Thursday (feb 6th) I went to UC because I felt like I had bronchitis but without the cough... Just felt very tight. Once there they noticed my heart rate (HR) was 147 and took my to the hospital via ambulance. My ekgs were all normal, CT scan was normal and blood work was elevated in areas. They admitted me over night and started an iv. Next morning my HR was down to the 80s so they sent me home. The next evening my heart rate shot up again. We to the ER once again and hr was raising whenever I stood up. They admitted me and kept me until Monday. This time my potassium levels were low so they gave me a pill. They also did a echo during this stay which also came back normal. WBC when first admitted was 17, 10 when I was discharged. I then set up a two week follow up appt with my primary dr for two weeks. The fast heart beat came back the same day day I was released. I seem very winded and tired and just want to lay down all day

I can feel my hr go up every time I hold a conversation on walk around. On Tuesday I got a new symptom, yellow loose stool. On Friday I went back to my general dr because I just felt so crappy and I couldn't wait until the 27th. My HR in the office when I got there was 141. Took a bata blocker and breathing treatment in the office and it lowered it to 98. Ran more blood work and my wbc is still a little high at 12.7.
The drs have now put me on a bata blocker (starts with a M) makes me feel even worst
Could a GI virus be causing all of this? Any idea what else this could be? Am I going to feel this crappy forever!
Please help!
Also, I have no appetite and have lost 6 lbs this week. I also have had no caffine since my first symptoms 8 days ago.