I had a temp dips when pregnant and not pregnant so it's hard to say. Normoly for implantation its around 8dpo tho. 5dpo seems a bit early but I cud be wrong.
I had a huge dip at 6dpo last cycle and then it shot right back up again then I had another at 9dpo but I'm now on CD5 of a new cycle so I wasnt pregnant. But I also had a temp dip 2 cycles ago at 8dpo and I was pregnant but it ended in a chemical pregnancy.
Good luck hon. I've been temping for 3 whole cycles now and now onto my 4th.
Hope u get ure BFP