Will

So I had yesterday after school and all day today with Will.  Yesterday I was able to forget all the worry while we had fun.  It was such a great day.  Today was a little different.  We started by him crawling into bed with me at 4:45am.  We slept till 7:45 which was a first I think.  We played a little, had a snack and a mini meltdown because I wouldn't let him have what he wanted for morning snack, went to the library, then to the Children's Museum where Will actually put his hand in the tide pool tank and touched everything from a real live crab to a sea star, to a sea urchin and other things besides.  I was very proud of him for being so adventurous.  May not be a big deal for most kids, but for Will it was huge.  We've gone many times when it was open and this was the first time he willingly wanted to do it.  He wasn't sure about the crab at first, but when the lady in charge picked it up and it didn't "get her" he got more bold.  He also asked the face painter if she would paint stars on one hand and a rainbow on the other.  He got me to get a dragonfly and then decided it would go right on my forehead for all to see.  Yeah me.
We then came home for lunch, played a little more, then went grocery shopping. Had a larger meltdown while there- growling at me, very rude, stamping his feet- got home and continued the meltdown telling me I was mean to him= rushing him in the store, asking him too many questions ( i asked him what he wanted me to get for his lunches- that's it!)  I pointed out that I got him a dress-up outfit for him and a snack he wanted, but these did not prove that I am not mean to him.  His grandfather came over and played with him.  He had dinner, played on the computer too much, short bath and then bed.  We are pretty sure he's coming down with a cold which means a runny nose, a lot less sleep for both of us, and a cranky demeanor.
As you can see, I had a lot of moments throughout the day that were a lot of fun, and I did my best to enjoy them without holding on to the worry.  But those moments of meltdowns were terrifying to me.  Not because they were big (they weren't) but because now all I can wonder is "Is this the one that turns explosive and damages him psychologically?  Will his self-esteem be permanently damaged by this?  Should he already be in SP?  Am I making the right decision?  Am I being selfish?
How am I supposed to know what the best decision for Will is?  I'm terrified that whatever I do will be the catalyst for him being forever damaged.  Is this how any mom would feel faced with this situation?  Am I just completely over-reacting?  Am I putting off what needs to be done immediately?  Or am I putting myself and more importantly Will through something he should never go through?  I know parenting wouldn't be easy, but this is killing me.  Now that I've basically made the decision that he will eventually go to SH I keep second guessing myself about if it's right or if the timing is right.
I think I might be slightly neurotic.  You think?????