What could be wrong with me?!
Question: What could be wrong with me?
My dear young man, I believe that the worse problem you have is the bad companies you are associated with. First you drank with them, then you smoked weed with them (maybe one of them supplied the weed?) Get rid of them. Better be alone than in bad company: I assure you, it will get worse, and will end up in trouble.
NOW YOUR question: You smoked in March, it is only April. Maybe your body has not eliminate all of the weed yet. You don't say how tall are you or how much you weight, nor if you practice exports, or exercise daily. All these factors may contribute to your dizziness, lost of focus, etc.
You should take minerals and vitamins if are not taking them. Have a good nutrition: lots of milk, no soda; meat, chicken, eggs, beans, in other words, lot of proteins. And if this does not help, tell your father (and if he is not around, tell your mother) that you don't feel well (the same as you said here) even though you don't need to mention the weed.
You may be also feeling the effect of puberty. At that age your body is going thru a lot of changes: you will be growing hair in your private areas, under your arms and even on your face. You will start to have "wet dreams" (Google what they are if you don't know) and your voice will crack once in a while, because you are becoming a man.
Please, son, don't use any more weed, don't try other drugs, don't drink alcohol, don't smoke cigarettes. BE CLEAN. I will keep you in my prayers. Trust me.