It is Normal to be like this,its really early days,and all your plans went when your mum did,also you are trying to make big decisions at the worst possible time.I agree living opposite your mums house now might be difficult,I think I mentioned before, that might depend on what happens too that house and who ends up living there.I don't know what the answer is,Are you happy in your current house,could you make a clean break and move somewhere else or could you bear someone else in your mums house.What if you kept some of her stuff or took some plants from her garden and moved them across the road,would that help.One thing you could try is writing down your options,then putting a list of pros and come next too them.Perhaps get your family to help with it because it affects all of you.Sometimes you will find one list is so much longer than the other,the best option becomes more obvious.
Difficult with work too I could go outside out of the way in my job but you can't just leave a classroom.Do you have a classroom assistant for the two difficult ones,Some people do allow a phased return so is that a possibility for you.
If not then at least you have half term not too far away.I don't know how it works now but my mum was a teacher and they took it in turns for playground duty,so four days she came home at lunchtimes.If you can leave the premises a brisk walk round the block might help you too recoup a bit.Just a thought but is there a link between work and home,so for example were you moving closer to work so you could pop in on her at lunchtime and would that still be important so you could nip home.