Oh Chelle, I am so sorry to hear you are worried.
Let me try & reassure you a bit here.
It is impossible to clinically diagnose PE prior to 20 weeks due to the development of the placenta, however, a placenta can start failing much earlier to produce symptoms. Having said that at 13+4 is is incredibly unlikely to be PE brewing.
It is more likely that you are so anxious that what you experienced was a bit of 'white coat' effect. The minute you go near anyone with a BP machine it goes up!
If the 160/90 really was a true reflection of your BP then it does indicate that you will be more likely to get PE again in this pregnancy but it is not a guarantee that it will, just more likely.
The labetalol can come in different preparations so it may have been a previously higher dose in one tablet as opposed to 2 lower doses over 2 tablets this time. Being a beta blocker, labetalol can also help with anxiety too, so if your high reading was anxiety based, it should help to manage that too. (Beta blockers can also cause low mood so do be aware that if you are feeling depressed it might actually be the tablets causing you to feel that way.)
Listen to your body, if you are worried knock on a GPs door until they listen & hear you...meantime why not ask your GP for some protein dipsticks (or get some from a chemist) if it helps to reassure you inbetween visits.
I hope this helps.
Warm Wishes
Liz