Does the pain from epididymis compare to being kicked in the nads repeatedly? That's what my pain feels like, knee buckling at times,

Epididymitis. Yes the pain can be very severe. The good news it with treatment (usually an antibiotic) it should clear up within a few days if not sooner.
If it lasts longer then I would return to your primary care physician or a urologist.
If the pain becomes unbearable then you should go to the Emergency Department.