i have to go to a doctor vs I has to go to a docotor

Some examples from the web:

• I have to go to the doctor.
• You have to go to a doctor.
• I have to go to the doctor. I hate wasting this, but...
• I have to go see the doctor at the home.
• If you have to go to a doctor or hospital, take the pack and this leaflet with you.
• I have to buy diapers, I have to go pick up the stroller, I have to go to the doctor.
• I have to go to the doctor. I can see you're in the middle of something very important here, so I'll let you know how it turns out.
• I have to go meet my new doctor.
• You have to go see a doctor.
• I thought she was going to go to a doctor.
• You need to go to a doctor for something like that.
• She needs to go to a doctor.
• She refused to go to see a doctor.
• Now then, I have to go lie to this doctor so that I am drugged-up enough for my job interview.
• Look, I saw the nanny cam footage, and you do not have to go to that doctor's appointment.
• All right, we may need to go to a doctor.
• Okay, you need to go to a doctor.
• It'd be easier to go to a doctor, tell him you need something to calm your nerves.
• I did what I could, but she's refusing to go to a doctor.
• I'm a doctor. I have to go.

Some examples from the web:

• I ha to go to work soon, so...
• I ha to go to work soon, so...
• My daughter has to go to school.
• There is no reason Howard has to go to that committee.
• Perhaps he has to go to the Advocate first.
• Your daughter has to go to the bathroom.
• Lady Mary has to go to London.
• Michele has to go to another debate.
• Somebody has to go to the moon pool and do it manually.
• Yes, mommy has to go to work now.
• My grandchild has to go to the toilet.
• It has to go to the refuse disposal plant.
• One sneeze and it has to go to the laundry.
• Sharee has to go to an actual foster home.
• Someone has to go to chang and talk to him.
• The court says he has to go to anger management therapy.
• Wait, I think Champion has to go to the bathroom.
• She has to go to press Monday with the leak.
• Javier has to go to New York.
• He has to go to one every day for two weeks.