WHM, with british fiance, and oops now pregnant

Hi hopefully someone can help me with this, I am currently on a WHM visa due to expire next May. I do have a british fiance, we have been together for 8 years, 7 in canada one here, we were planning on getting married next year but I have just found out i'm pregnant, and don't really want to get married with a pregnant belly, I also feel I'll need as much money as possible for when the baby arrives.
Anyways we do plan on returning to canada, but the baby is due at the end of march and i don't want to be flying 8 hours plus with a newborn. Does anyone know of anything that may extend my visa long enough for the baby to get old enough to fly(I'm thinking around 6 mo or so). Do i have to go for a FLM unmarried partner, or can i just get some sort of extention due to the fact that the baby will be a british citizen and be dependent on me, as well as the fact that i do not intend to stay in england long term?

My fiance also has a few problems with his canadian immigration as he was illegal in canada for 7 years (went on a 6 mo visiters visa and never left) if anyone has info on that as well that would be really helpful as well.

Thanks so much

There is no extension possible on a working holiday maker visa so you will have to apply for a unmarried partner visa. It is probably a good idea to do this as you mentioned that your fiance was illegally living in Canada , it may takes a long time before they accept him again !

Good luck