What Causes Short Term Memory After Smoking Up Marijuana?

Hi I have a question. I dont usually smoke weed, but about a month and a half ago I smoked with some friends. The next day I was in a haze and couldnt think straight and I had really short term memory as if I was still high. I would go somewhere amd I couldnt vividly remember where I had come from. I was in this haze for weeks and am still feeling it a bit. I havent had any alchohol since, except for a beer one time. I am in college and am worried. I was wondering if anyone out there can help explain this. The pot was not laced, my twin brother has had a similar thing happen so it might be genetic and the people with me were fine the next day. I asked them. I only took one hit of a bong. Please can someone help me? Whenever I run around a little bit.