I find the tea thing hard. I often end up taking it with tea.
The key thing is consistency. And being as consistent as possible in the few weeks before a test. As the test will reflect what dose you should be truly on.
As Mrs T says, T4 half life is quite long - about 7-10 days (think depends on your general levels) so one missed dose will not be felt the next day or week etc. Similarly, taking a double dose after a missed dose shouldn't cause an issue. However, one missed dose a week could be the difference of 25 less over all. If it went on for a few weeks it could impact. But, the soonest ideally a GP can test after a dose change is 6 weeks as this is how long it takes to build up within the blood.
I find it helpful to think about the amount taken over a week. So if on 100 daily, you take 700 per week. So taking a double dose after one day missed dose is ok as its still 700 within the week.
Alternatively, spread it over a couple of days (not easy to split tablets).
Other foods inhibit a percentage absorption hence empty stomach.
Incidentally, grapefruit lessens the way thyroxine is metabolised and the effect stays in the liver for a few days after consuming one, so best to stay clear.
All these things are tiny adjustments to the dose but could add up over all over time.
Pre child I could easily take it within my daily going to work routine. I used to work out what date I should finish the box on and write it on to double check. But now with a toddler I've found a pill box is easier, with a tiny cup of water next to it on my dressing table (out of sight/ reach of toddler).
So basically op, you could take an extra dose today and just try to carry on as normal.