Welcome fo the forum. Thanks for your question.
Fellatio (oral-penile sex) is safe sex. A few HIV cases may have been acquired that way, but even this is unproved -- some experts believe the risk is truly zero. The thread below address the HIV/STD risks from fellatio. As you will see, it contains links to still other detailed discussions.
Your symptoms started much too soon to be due to ARS from this exposure; 8-10 days is the minimum. And they aren't typical ARS symptoms anyway. It sounds like you have a minor cold, allergy, or similar problem.
For those reasons, from a medical or risk standpoint, there is no need for you to be tested for HIV or any STD. Howver, if you remain nervous despite this reassurance and would feel better with a negative test result, have an HIV test at the apppriate time: defiitive results are available at 4 weeks for a duo test (HIV antibody + antigen) or at 6 weeks for a standalone antibody test.
I hope these comments are helpful. Best wishes-- HHH, MD