You are almost certainly fine. A prolonged erection is not always a medical emergency priapism - especially in young men.
Ischemic Priapisms are when the blood is nearly totally trapped in the penis and it cannot get out. If the blood is able to flow from the penis during an erection, you are fine. If you had an Ischemic priapism, you would experience extreme pain and the penis is usually dark, smaller, and painful to touch. It is less likely to cause any damage if blood is still able to move through the penis. If you are able to get erections now, you are probably fine. Also, sounds like you don't really need the cialis.
Read This:
https://www.mayoclinic.org/diseases-conditions/priapism/symptoms-causes/syc-20352005#:~:text=Priapism%20is%20a%20prolonged%20erection,priapism%20is%20a%20medical%20emergency.This article states:
Ischemic priapism, also called low-flow priapism, is the result of blood not being able to leave the penis.
Blood is trapped in the penis because it cannot flow out of the veins of the penis or there is a problem with
the contraction of smooth muscles within the erectile tissue of the penis. Ischemic priapism is the more
common type of priapism and requires immediate medical care to prevent complications caused by not getting
enough oxygen to the penile tissue.
Signs and symptoms include:
Erection lasting more than four hours or unrelated to sexual interest or stimulation
Rigid penile shaft, but the tip of penis (glans) is soft
Progressively worsening penile painLay off the cialis. If you need it for confidence, find a sex therapist to help deal with performance anxiety so you don't need the drugs.
Paul