Agree that you appear to be on the good side of typical regarding bladder performance, which is excellent news.
Tadalafil (Cialis) is for erectile dysfunction, and early use of this in order to get erections is considered the best way to rehabilitate/improve blood flow down there and lead to the quickest and most complete recovery of erectile function. As I understand it there is little point in taking the drug without a bit of “practice” as well. Sounds like you haven’t been very well briefed!
Unfortunately, Tadalfil and it’s perhaps slightly better known relative sildanafil (viagra) do have a tendency to cause headache and runny nose in some people. Primary effectiveness and side effects vary with the individual. For me, sildanafil is very effective, but also always gives me a thumping headache for 6 - 8 hours, which seriously reduces my enthusiasm for it. Tadalafil is much less nasty on the side-effects front but also less reliably effective, though this also offset by being longer lasting with a single dose providing some effect for a couple of days.