I had a causal relationship with a guy, we had unprotected sex (yes i am fool) hiv test came back negative will my next one be negative in march ?

Hopefully yes: But that does not mean that you should avoid being retested. Follow-up is very important. In addition make sure you have also been tested thoroughly for other stds, particularly syphilis. Even if you were with him previously not every sexual encounter with an hiv+ person transmits the disease. Go and get tested again in march. And stop having unprotected sex.

Let me explain: Tests may be falsely positive or falsely negative. It can take some time for the immune system to produce enough antibodies for the antibody test to turn positive this time period is commonly referred to as the "testing window period" and may last six weeks to three months following infection. Therefore if the initial antibody test is negative a repeat test should be performed three month later.