First, it is definitely not "freak-out" time.
Anything that acts as a vasoconstrictor will be detrimental to erections. It is well known that smoking and any product that contains nicotine (a vasoconstrictor) is a long term risk to the cardiovascular system.
Erratic blood sugar either low or high and this can be caused by not eating or eating something after a period of unintentional fasting can also play a role.
For the long term I would give serious considerations to making tobacco a part of your past, because if you don't E.D. (which has many causes) can become a part of your future.
People who are unusually large in size as aging takes place are more prone to erectile problems because of the symple hydraulics governing erections. Larger blood volume and more demand based on erectile vascular structures tends to create problems.
From what you have said, you tend to lead a healthy lifestyle in general with the exception of smoking. Also be aware that there are a number of over the counter medications that can affect your noodel too. Most of the worst ones are cough and cold related.
Calm down, don't let your imagination conjure up horrors of a permanently limp noodle and think about all of the things that happened in the 5-7 hour period prior to your meeting the young lady and then the event to follow. Food, tobacco, alcohol, medications, and then come back to us with that too. There may be something obvious that jumps out with that information.
Saying good bye to the smoking in general is a good deal. I do not know how much you smoke, but, if it takes this to get you to give it up, maybe that bout with ED was one of the best things that ever happened to you.
Good Luck. . .