Hi Doctors. I’m 5 weeks pregnant and it’s my first pregnancy. Should I see my GP or should I rather see an gynecologist.

Who to see? Some family practice doctor do obstetrics. They are usually covered by an obstetrician that can be consulted if the need arises. Check to see if your doctor does obstetrics. If not, you should see an obstetrician.
Either. For the sake of your and your baby's health, you should see a doctor soon. Either doctor will be okay.
Wish you good health and a healthy baby!
Start with OB GYN. You need to begin this pregnancy journey with the MD who will complete the trip with you and that is the OB GYN MD.