Irregular heartbeat on TRT

[Bonaparte]

You need to get rhythm checked via ECG or an Holter, you cannot tell an irregular heartbeat from feeling.

Palpating a pulse works pretty well for detecting an irregular heart beat (since you'll only detect perfusing beats). Now, if you want to actually tell what's going on electrically, you'll need an EKG (really just a rhythm strip, but they'll do the full 12 anyway).
You're probably throwing PVC's, which can feel weird. There are dozens of factors that can cause or exacerbate PVC's, mainly stimulants and other things that increase sympathetic nervous system activity (hunger, sleep deprivation, etc). So you may need to lower the dose and/or look into beta blockers or other antidysrhythmics to get this under control.