Scared about bacterial infection or flu after seeing doctor

Okay, I seen one of the doctors at my practice 2 weeks ago, as I was having palpitations. He said I was fine, and sent me on my way. Then, my mum started to feel ill last Monday, and it looked like the start of flu. Then, Tuesday, I started to feel unwell, starting out with a sore throat, and palpitations. This got worse through the day, and I went to my emergency caredoc at 11pm that night. He took my pulse, and said it was a 150, then after 10 minutes, he took it again and it went down to 120, and down a little after that. I decided to go to my doctor the next day. Wednesday, and I go see my own doctor, and took my pulse which was around a 120 as well, and went down a little. Anyway, she took a blood test, and arranged an ECG.

I got the ECG done today, and the nurse said my blood pressure was high as well at 121/92 or 126/96 readings on the paper. So I went into my doctor, and she started to ask how I was feeling, and I said I wasn't feeling great, I had a sore throat, coughing, and now had a runny nose. She said that would line up with what the blood tests were showing. She said my bacterial markers in my blood were through the roof (I think that's what she meant, or worse to that affect). Anyway, she said the infection wasn't coming from anything (not sure what she meant by this, like in my body or something). She took my pulse and temperature, and said she was giving me antibiotics (clarithromycin 500mg for a week). She said my head was fine though, just the palpitations, which she said was likely due to the infection.

Btw, I'm 30 yr old female, Hypothyroid, I don't drink or smoke.

Anyway, I'm feeling a bit scared after seeing my doctor, because she also said that if the palpitations don't go away, she will send me to a cardiologist and see about going on medication to regulate it. I'm scared about all that was said, the bacterial infection as well. Two days ago, it was really bad, I had the blood tests Wednesday, and whatever it is, got really bad Friday and Saturday, but eased down yesterday, and my throat isn't hurting anymore, its just a really runny nose, coughing, which I think is causing my head and eyes to hurt. I'm not sleeping much, but I am eating and swallowing normally.

Yeah, I just feel panicky like, is this bacterial infection / flu thing going to turn deadly? I'm on edge now. I already suffer with really bad anxiety and depression, so naturally it makes me very worried. I'm starting my twice daily dose of the antibiotics in the morning, or should I start one right away tonight? It says twice daily, so not sure if I should start fresh in the morning?

I'm trying to eat lots of healthy bacteria fighting food, but I don't have a lot of money, so I'm doing my best. I've been keeping warm, and staying in bed mostly, but I still have to walk my dogs though. My chest hurts from all the coughing and whatever this thing is.

My mum is coughing a lot too, she still has a bit of the sore throat, and the doctor said (to my mum as she was with me), that its passing back and forth because we're in the same house. So, yeah, I just feel scared, worrying if it will turn deadly? I can't sleep.

So, I'm feeling a little scared.