Parasites and racing heart?

Hello - please help me not feel nuts. I am a new user of this site, but I've been reading your forum for a few weeks. Starting in February, I started getting an upset stomach (pain, diarrhea) and a rapid heartbeat. I was on zithromax at the time, which I then stopped (but had to take subsequently for a sinus infection).

The symptoms didn't abate, and I went to see my doctor. She is a homeopathic / holistic doctor (though she is an MD). She told me that Zithromax does in fact cause heart arrythmias, which I already knew, but that it usually only does so when the person has a parasite (which sounded weird to me, but that's ok). Based on my symptoms, she thought I had one. Additionally, I had some tests recently showing that I was basically in adrenal fatigue, with heightened levels of certain neurotransmitters, including seratonin.

I started her parasite protocol a few weeks ago, which is a rotation of Albenza, Alinia, and Stromectol. For a month or so before that, I took Gaia Herbs formula for parasites (on my own).

What I am wondering is whether (a) parasites could cause my heart to race and my body to feel like it's in "fight or flight mode," and (b) should these symptoms be going away? My stomach is feeling better, but the adrenal stress still seems to be there. The alternative diagnosis is a neuroadrenal tumor, which they don't seem to think I have, so I'm hoping parasites it is.

Thanks!