Pregnancy symptoms coming and going at 7 weeks

Hi everyone I have had four previous pregnancies but can't remember what they were like at the beginning with pregnancy symptoms I am currently 7 weeks pregnant and some days I have symptoms and other days I don't, I am only concerned as I had a missed miscarriage in March this year, it doesn't help that I constantly stressed out about losing this baby also I have had constant headaces for the last few days, I have had a scan done and the baby's heart beat was 122 at 6 weeks and 3 days, please share some thoughts or experiences
Also just to throw it in there that yesterday I had bad morning sickness and diarrhea yesterday and not much today