A reading of 140/80 with a mild headache, especially after 149 the day before, is on the higher side for your age but not an emergency, more so since your other tests came back normal. It's worth tracking rather than ignoring.
Next Steps
Check your BP at rest, same time each day, for the next week, and see a general physician if it stays over 140/90 or the headache continues.
Health Tips
Cut down on added salt and caffeine meanwhile, and get checked sooner if you get a severe headache, blurred vision or breathlessness.