What can I take for constipation while pregnant?

I’m 12 weeks pregnant. For the last few weeks I’ve been extremely constipated. It’s so bad rn I can’t even eat. I throw up 3/4 times a dayBut my main problem is I called my ob because I feel like my throat is full. Near my collar bone. And I keep burping. She said I need to see my PCP for that. Any ideas on this? It started when I got constipated. She said it isn’t pregnant related tho