Thanks coff33. Your poor dog, hayfever is horrible. Mine has a grass allergy that gives her itchy paws, not good for a dog that wants to spend half her life in the garden.
Sounds like your ds and my ds1 were both on a mission today. I think its par for the course at this time of year with all the end of term disruption. Sad thing is, we'll just get them properly settled and relaxed and it'll be time to send them back again.
We do the sending them to different parts of the house thing as well, but just recently ds1 has reverted to his old fear of being upstairs on his own, which means that particular strategy is no good at the moment.
I hate it when things go wrong and I can't get a handle on why, especially when they've seemed to be going a lot better recently. I sometimes feel like life with ds1 is a bit like a rollercoaster. There are a few slow and steady bits where things trundle along, but they usually precede a blooming great drop from a great height when things all get very stressed and often scary. Then there are the loop the loops where everything feels like its upside down and out of my control then just when I think I can't take anymore along comes another lull. It does help when things get hairy to know that there will be another trundle along sometime soon, iyswim.
You're right about the relapses, except I'd say they aren't so much relapses as 'reactions' to whatever's going on at the time eg end of term, holidays with unstructured time etc. Weekends are particular flashpoints for many children with ASD, as they cope better in a more structured time framework. Ds1 has been all over the place today because we had to be out of the house for the inspection, then had to wait at my Mum's house even though she was out, then there was all the dog stuff and me being upset. We usually keep Saturdays very quiet as a day to recover from the week. So, pjs for ds1, his favourite tv programmes in the right order in the morning, lunch at the same time and then ds time. If we do have to go out, we try to follow a semi-structured pattern time-wise and throw in something at the end of the sojourn that he will find rewarding to keep him motivated.
I think night-crying is common among us Mums as well. We have to hold it together so much in the day and get so little time for ourselves that its the only chance we get to let it out. 
At least we can come on here and support each other though - I'd be lost without this place.
I try to remember the thing my mum once told me (she's a clinical psych) about 'the good enough mother' or rather 'good enough parent' . Winnicott said basically, that perfect mothers/parents are bad for children. If we were all wonderful stepford mums, who were always sweet and kind, had endless patience, kept perfect houses, did everything for our children and never made mistakes - our children would grow up, leave home and immediately have a breakdown, because real life just isn't like that. We would be doing them no favours, as they would never learn either to take care of themselves or to understand that its ok to be less than perfect, leading to overly high expections of themselves and potentially damaging self-esteem issues if they fail to meet their own unattainable high standards. In addition, they would grow up never learning to accept imperfection in others, setting their expections of others too high and ultimately sabotaging every relationship before it even starts.
Its alright not to be perfect. What matters is that you care about trying to do things right, acknowledging when you get things wrong, caring about how your actions affect those around you and adjusting them accordingly. Without us making mistakes, how would they ever learn the importance of apologies? These are some of the most important things our children (particularly those who have ASD) need to see modelled.
I find it helps to think of it as being perfectly imperfect! 