I think she will simply have felt overwhelmed and panicked by the sheer volume of knitting - multiple items with five months to go is quite intimidating when she almost certainly hasn't given baby clothes a thought yet. A bit like if you'd excitedly shown her into a fully-decorated nursery in your house. She may have felt it was presumptuous even.
Also, you say they're nice patterns but I've been given baby knits in nice patterns but horrible yarn before so it may be that it wasn't the knitting itself so much as the colours/yarn she was objecting to.
DM has to be physically restrained from knitting for my babies
but the compromise we have reached is that she does tricky things in milk cotton - so she gets lots of time knitting and the good feeling of giving, but I can still dress my baby in 100% cotton or bamboo (I react to wool and manmade fibres are too hot).
Blankets are very time-consuming, interesting knits, especially if you do a cot bed size rather than receiving blanket size. If you were to offer one of those, in agreed colours/yarn and patterns, then it would probably take you most of the rest of her pregnancy and create an item you can both love.
I honestly think she's rejecting neither you nor the knitting itself, just the timing. You probably shouldn't have sprung it on her while she's vulnerable. I'm sure she didn't want to hurt you but just panicked and scrabbled about for a "no thanks" that wasn't "dear God, mum, we aren't out of the woods yet, stop tempting fate".