Can being sick impact implantation?

I am sick as a dog today. SO got sick early yesterday, coughing terribly and has been in the bed for two days. Last night I started getting throat tickles and today I have a fever of 100, highest was 101.0 and my head is killing me. Guessing the flu but he went to the doctor and all they said was keep taking nyquil and dayquil and advil. I didn't see a point in going to the doctor is that's all they told him. I am supposed to be 5dpo today, but I haven't charted or checked CM this cycle. I will test the 15th if AF doesn't show up the 12th. Didn't know if there's a chance this could make it even harder to get pregnant this cycle?