I very much doubt that you have the flu.
It is more likely to be an infection.
Yes, I would agree with you that you have infected your wife.
I suggest you and your wife make an appointment as soon as possible to see your doctor urgently and also get checked out at the GUM clinic. The sooner you get the correct diagnosis, you will be able to get the appropriate medication to get better. If this is a sexually transmitted disease, the sooner you get treated, the better.
With regard to your question, you are correct in fearing the worst. Even though you used condoms with the sexual encounters that you had, this would give you some protection, but no doubt there was still body contact. Then you had unprotected oral sex. Don't be fooled that you can't get infections from having oral sex. At the end of the day, in taking part in oral sex, you are exchanging body fluids. Sexually transmitted diseases are not always confined to the genital area.
I hope that you have a forgiving wife and that this does not hamper your relationship with your her. In the meantime, I suggest that you and also your wife do not take part in any sexual activities with each other or anyone else (sounds like you are not well for that anyway), until you get checked out and treated appropriately.
I also suggest that as a matter of urgency, you book yourself and your wife to get checked out by your doctors and at the GUM clinic.