Sunmonkey
Not totally clear but sounds like your DS is in school in Holland - and as an aside we also start school here, year turning 5 (so at 4).
I presume he's still in his first year of school. But perhaps you mean he's in his second year of school.
If first year (so = kindergarten or reception here in England): It's so incredibly hard to know what's going on. He won't have the verbal skills to say what is happening in class. I think there is a worry there for you but can't be certain whether he's upset over nothing or he is being singled out.
I'd play innocent and ask about the zipper thing - it could be that there is a simple explanation. She does want to help but he asked her at a bad time (when she was speaking to another parent or busy helping another child). Often very young children don't appreciate someone is busy doing something else and can be very hurt if you say no.
If this is his second year at school (= year 1 in England) - then this could be that they are gradually trying to shift to a more independent pupil and more formal learning. She may be doing this to everybody and so isn't particularly picking on your son.
One thing that does occur - if you have missed school time, you can come back and feel really out of touch (a week is a long time in school, not just politics). DD1 was off sick for two weeks and found returning to school really odd. There were all sorts of things going on in class, in playtime, with friends that she didn't quite understand. Fortunately they then almost immediately broke up for a long holiday - so she started fresh & feeling better in herself the following term.
In terms of the ripped up picture - DDs have had this - (see lefthanded feed). Awful for a child, especially if they've put a lot of their heart and soul into the work. Again maybe mention that your son is saying you threw out his art work - and play innocent, surely he's misunderstood. however, he's still upset about it so you wanted to know more about what happened to help him understand what's going on.
I hope there is a simple explanation and that this little wrinkle in things school smooths itself out shortly for your DS.
Not sure about the high voice requiring speech therapy. Boys often have artificially high voices that lower considerably after puberty. I suppose the question is better put to your parents (if still around) and whether this seems a particularly high voice in a boy (especially if you or your DP have brothers). Take the suggestion as sincerely meant - and ask what they recommend you do next or will they arrange a speech therapist in school. (My DD2 often ignored her teacher and they worried she had ear problems. We had her tested and found out she didn't have a problem. I think the teacher was a bit hurt that DD2 was just not listening to her, but the teacher devised a kind of sing song way of calling DD2s name that DD2 would instantly respond to (and made DD2 feel special) and the problem was solved. Eventually she just learned that not listening meant you don't understand what's going on, so she tried harder to listen).
HTH