Thank you very much for your post and welcome to our forum.
I would not go as far as not having sex ever again as that is not a good option either. I would suggest that safe sex is a very good alternative option and if you had used a condom, even for the brief penetration, you would not be having all these worries now. Anyhow, we are all human and sometimes we all make mistakes like these.
Any unprotected penetration, even without ejaculation, involves risks, including risks of HIV infection. The risk is always higher for the person being penetrated. Incidence of HIV is high in South Africa as well as higher among gay and bisexual men: risk is higher for uncircumcised males. Therefore if we assume that he is positive, the estimated risk for you is approximately 3% or 1 in 33, which is significant. This is probably lower because your penetration was quite brief and also we do not know his status.
Looking at symptoms is not usually the best approach because, even though most people would get symptoms of sero-conversion, many would have mild symptoms or no symptoms at all. And the symptoms are non-specific, being consistent with hundreds of many other common conditions. If you are able to have a PCR RNA test (or NAAT) for HIV-1 and 2 as soon as possible, that can be considered conclusive straight away. However you could also have a simple antibody test, which, if negative, would at least exclude the symptoms you have been experiencing as related with HIV sero-conversion and would be reassuring, even though not conclusive. Alternatively a HIV Duo test after 4 weeks would be totally final and conclusive. Having said that, you could always have a Duo test now (testing for the antibodies and the p24 antigen) which would be highly reassuring as well as it can detect the p24 antigen already after 2 weeks.
I am giving you all these options because you need to have peace of mind as soon as possible.