Sickness or pregnancy related symptoms

Mia

Hi guys - I’m 20 weeks with my first and have been struggling with nausea throughout, however today is really bad. I feel really weak,tired,headache and feel really dizzy, I didn’t know whether it was just that I needed to drink more so I’ve drank and eaten more but still have 0 improvement. I haven’t felt this bad other than when I was 12 weeks ish. Can symptoms just come on like this or is this more something I should check with a doctor x