Feeling miserable

Hi ladies,
Just a question from my side. Since the beginning of this year, I've stopped using contraception (NuvaRing) and have been trying for our first baby. Out of curiosity, I've started doing ovulation tests again this month, using the Clearblue Digital tests. I started testing from day 11, and last Sunday, the test showed a smiley. We usually have sex every other day throughout the cycle. Since yesterday, I've been feeling dizzy in the morning, which sometimes scares me. It feels like I'm about to faint. I thought it might be low blood pressure or the hot weather, so I assumed that was the cause.
Normally, I don't go googling much and just see what happens. But this morning I read that it can also happen after ovulation/fertilization. It seems unlikely to me to have 'symptoms' this early (a week before my period). I definitely don't want to assume yet that I might be pregnant. I'm not in the mood for disappointment.
Maybe someone has experienced this too or has other tips?

Love