I've been taking vyvanse for about a year & quarter, it has worked. But today things changed, recently I've been taking 40mg with 30mg pills(splitting one into thirds and taking a third with a full one) and it worked, my doc gave me the full 40 and yesterday it worked, I think, but today it seems less effective, if not making my add worse, I can't do any work at all. I haven't changed my diet at all l, I've been on 40 before and it worked. Could the vyvanse have stopped working?