There is no evidence that there is any effect on the stimulation or embryo quality. Try to keep a very flexible schedule the week before the pregnancy test. Some people start their periods early and are stuck somewhere where they cannot just be alone and grieve. If it's painful to have blood drawn, ask the nurse to use a butterfly needle. It's smaller than the regular one, and you may find it hurts less.
Infertility is a nightmare, and it's very difficult to go through it without support.
Talking with other people going through the same thing is absolutely wonderful. The rest of the world doesn't usually get it. There's nothing like being able to share experiences and support with other people who are in the same boat as you. Some clinics believe that a diet that is high in protein and low in salt and potassium can help you avoid hyperstimulation. Some people really have pain because their ovaries are so stimulated and this may get worse as the follicles ripen.