7 weeks and so scared

Hi. Im seven weeks and 2 days and I am petrified something is going to go wrong. I have sickness every day but changes from the morning to the evening to all day on different days, Im still getting cramping which gets stronger in the evenings, I work in a nursery so I could be over doing things. Im so constipated and all baby is letting me eat is crap food. If I eat fruit and veg or a healthy meal it comes straight back up but if I eat a chocolate bar it will stay down! Anyone who can offer some reasurance? xx