Someone help.

Brianna • 18 years old, partner 20 years olds, pregnant with our first..and second! And we're both over moon excited for our twins
On Tuesday morning, I woke up and feeling so ill, I ended up spewing and I was all good after that. I haven't thrown up since but I've been constipated and I can't eat anything, I feel way to ill, I'm so exhausted and just feel sick all the time. does anyone know what this could be caused by?