Hi, welcome to healthcare magic, congrats on the pregnancy
. I am sorry that you feel unwell.
It is thought that a high temperature can be harmful to the fetus in the first trimester but after this point , especially in the third trimester when the baby is just increasing in size it is unlikely to have a detrimental effect.
At 5 weeks you are still in the 1st trimester and a prolonged fever
can have harmful effects, the key word here is prolonged. If the fever does not last beyond 1 to 2 days then it is unlikely to cause any problems.
Treatment would include: tepid sponging with tap water, using a fan to cool your body, drinking cold
liquids and avoiding drinking hot liquids, removing any excess clothing, and using acetaminophen
which is considered safe in pregnancy.
If the fever continues despite these measures or if you remain concerned then you should consider visiting your doctor for a check up.
I hope this information is helpful to you and I wish you and your baby the best.