No period?

I've been tracking my period for about 6 months now and they are usually 33-34 days but the longest has been 38 (when I had food poisoning 3 months ago) this month I used opks and pretty sure I ovulated on June 8th or 9th which would make me around 18 dpo today. I took a frer test yesterday morning and it was neg. could i still be pregnant? When should I make a doctors appointment for a blood test or does anyone know/ have a similar expirience with what is going on? We've been trying for only 2 months. Thanks so much, appreciate your input! 😊