You know what one yr olds like doing best? Just pottering, exploring their world, making sense of things, discovering. When they totter about the house obsessively lifting the curtains or trying to press all the buttons on the washing machine, or they're outside yelling with excitement at seeing some ants on a leaf or a funny-looking plant, they are gaining very important things that structured activities just cannot give them. They need space to not 'do' in the way that we adults think of doing things.
And, my dear, so do you. You are piling so many expectations and activities on yourself that you are surely going to go under. Who are these people who will be disappointed in you? And most importantly, if they exist and they judge you so harshly, why should you care about their opinions?! Stop worrying about disappointing anyone else. Paradoxically, by stretching yourself so thinly, you DO run the risk of disappointing the only person who matters not to disappoint - your child, because they will have an anxious, stressed, haggard mummy who they don't get enough time with and who might well make herself illbh doing too much.
Have you always been a perfectionist or has your DH's illness given you a scary feeling of 'life is short'? Or perhaps it has made existing perfectionism worse?
Here's the secret to perfectionism: you will never be good enough, never do enough to satisfy that voice in your head telling you that you need to do more, need to do X, Y and Z and then you will be perfect/good/acceptable/loveable (whatever the need is within you that makes you this way). Nobody is perfect, life isn't perfect and fun and beauty can be found in the flaws. Think about someone you love, maybe a deceased grandparent- I bet when you remember them with love, you have a laugh about their daft foibles! Do you expect and need everyone else around you to be perfect? Of course not, so cut yourself some slack.
You're doing far too much. To throw another child into the mix would be the worst idea possible. I also think it's a folly to get pg fairly soon after one parent has had a very serious illness. The family needs to readjust and, to be blunt, you need to give it some time to make sure it does not come back, sorry. There is no magical 'perfect age gap'. Whatever the age gap between your children will be the perfect one for your family, be it 1 year or 15 years!
It sounds like you're doing so much so that y don't have to face horrible feelings within. It must've been terrible watching your Dh suffer with such a scary illness. Did either or both of you get counselling? You can't just snap back from something like that and running away from it by overwhelming yourself won't work.
You need to look after yourself and think about yourself. Cut back on the things that don't matter and just do less in general. You won't lie on your death bed fretting about household tasks and things at work you should've done, trust me.