Ghost pregnancy symptoms after chemical ?

I would have been 8 weeks pregnant this week. I have been nauseous and nothing is sitting right in my stomach. I thought it was some stomach bug but it’s been like two weeks now. I have also been completely exhausted. Both symptoms are very similar to my previous pregnancy.

The dr followed my hcg back down to 0 and I took another test this weekend to be sure and it was negative. I don’t get it.