Negative 14 dpo

So I'm 14 dpo just based off glow. I haven't been using opks or even charting really. I got a bfn on a pink dollar tree test this morning but I'm not feeling myself lately. I'm very congested, queasy, my boobs feel heavy, and I'm so tired. Has anyone ever gotten a negative on a dollar tree test but ended up being pregnant? Should I go get an frer?!