Welcome to the forum.
I agree this was a high risk exposure. But even in the highest risk situations, HIV usually is not transmitted. When a male has HIV and is the insertive partner (top) in anal sex, the anal partner (bottom) has 1 chance in 200 of catching the infection. The chance you were infected is lower than that, because your partner probably isn't infected, and the unprotected insertion was brief, without ejaculation. The condom-protected penetration was safe. So maybe 1 chance in 1,000 you could have been infected, as a rough guess.
You would have been a candidate for PEP, but it's too late now (72 hours maximum). You should see a doctor or clinic with experience in HIV and its transmission. Depending on the tests and clinical services available, you could have an HIV nucleic acid (DNA/RNA) test in a few days, followed by testing for HIV antibody, perhaps with p24 antigen (duo test). (If you are in Thailand, you should be able to find expert clincal services. However, if you have returned to China, I'm afraid I have no knowledge of HIV clinical serivces there. Most likely they vary widely, depending on city, province, etc.)
In any case, the odds are strongly in your favor. Good luck--
Can I add a little information about China?
At least in Beijing, there is a leading infectious hospital (Beijing Ditan Hospital) that specializes HIV/Aids which initated the cocktail treatment in China. Its founder was in the same team with David Ho in Aaron Diamond lab in NYU. It does all kinds of hiv tesing, including the 4th generation Duo test, among others.
I hope it helps.
You can get the test at Anonymous clinic (Thai Red Cross Society) which located in downtown area and accessible via BTS. They do offers Duo test and NAT test. It is one of the best HIV/STD Clinic in Thailand.
Telephone: 0-22522568-9 Ext 200
or you can go to one of these hospital. They have Duo test and PCR.
(1) BNH Hospital
(2) Bamrungraj Hospital
(3) Bangkok Hospital