Starting out on TRT, HCG and anastrozole is pretty much the wrong way to start things out, with a bunch of compounds. You should have started TRT in isolation, but not everyone does well on large or even moderate injections of T.
We don't know if you're going to be one of those guys who gets wrecked everything you touch and AI (AI over-esponder) or whether or not you're going to respond to HCG positively or negatively, kind of hard to tell starting out on so many different things at once.
I already suffer from general health anxiety, so these palpitations are terrifying.
This pretty much changes treatment, you need smaller more frequent injections because cypionate can cause spikes in testosterone and estrogen which can affect those with anxiety.
When I inject EOD, the peaks are smaller and so to are the effects from those peaks, these peaks and valleys affect everyone differently, some are prone to aggressiveness and other anxiety. When I inject small doses daily, these peaks are barely noticeable and it's smooth sailing with minimal peaks at all therefore no sides effects.
These palpitations is your body adapting, generally men experienced them for the first couple of weeks until levels are stable at 6 weeks. I see HCG causing a lot of problems with men, anastrozole is another frequent cause of suffering if dosed inappropriately.
I can't handle even 1/8th of a 0.050 anastrozole without serious side effects. At 5 weeks I'm feeling similar to the way you describe, most intense by 5.5 weeks and then everything calms down at 6 weeks.