I took 2 extra strength tylenol (acetaminophen) and an excedrin migraine this morning -- is it safe to even drink coffee?

Too much Tylenol (acetaminophen): A cup of coffee following a dose of Excedrin is likely to cause excessive jitteriness and increase your heart rate, since both contain caffeine. In otherwise healthy people this should not be a dangerous situation. However, Excedrin and Tylenol both have acetaminophen which can be damaging to the liver, and it is not generally recommended that they be taken together.

Caffeine overdose: Excedrin migraine already contains caffeine. There are many types of headaches, including migraines, cough, cluster, occipital neuralgia, muscle strain, etc. Keep a log of the timing, duration, severity, and location of your headaches. Also try to identify any headache "triggers" (stress, not sleeping/eating). Take this log to your physician. http://www.nlm.nih.gov/medlineplus/headache.html