Poor old you. It's just that little bit of time for yourself, beytween them asleep and you asleep - and you're not getting it. You can take the world on if you get a sit down and night's sleep but at times it's like there's nothing but feed, change nappy, burp, repeat.....
Here's the thing. Child will sleep if very tired. So what does s/he need to get tired. Does s/he attemd nursery? If not, try for every ay to get a subsidised place (if this is your need). We are genetically ntended to live in herds, where the babes and toddlers would crawl about together. No mum on her own no matter how super can substitute for this. So kid might be ratty from under stimulus.
And fall-back number two - sleeplessness doesn't last forever. As child develops and runs about more, they will sleep more.
it just feels like forever when you're n the middle of it.
Lastly, if there is an underlying cause you can ask at your GPs for help. Help to say there's no underlying cause or advice on how to cope.
Like others have said, a household where regular routines are observed is a fundametal, so hopefully this is the case with you.