CHEATING?! should i belive him or not?

the other night my boyfriend (of 6 months) called me and we talked for about 5 minutes, and then he said he had to go because he wanted some "me time"... then he called right back and said i could go to his house until 8 and i didnt question him or anything until i got there. when i finally arrived he was acting funny. he had some hennessy privlege and a blunt (weed and alcohal for those of you who are illiterate of what those are) and i asked him to pour me some priv and he was like no thats for my grandma... and then i asked him why he had to go in at 8 and he said well i have to fix my grandmas computer (at exactly 8 o clock?! wtf.) then he went outside and was texting someone and i saw that it said are you still comming and then i was like uhh wtf i didnt say anything but then he went inside and took a shower and got dressed all nice and asked me to run to the store to get him some crazy glue to fix his earing. WHO was he trying to impress. THEN this idiot left his phone in the car so i cheaked it out while i was out getting the crazy glue and i was right about what the text said and they replied *yea.* so i didnt say anything i went back to his house and then i just acted like i didnt care.. then i called him when i got home and then he said call me in an hour. so i did and then he told someone he would be right back and i was like who was that he said my grandma. i said whatever pimp and then he started calling me crazy because i went off on him and then hung up on me and then i kept calling back and they kept hanging up on me i was like wtf and then the gurl was sayin tell that gurl you chillin wit me right now and then the ********* answered the phone talkin bout hes busy eating i said yeah i bet hes eating all right and i was like well who the f.u.c.k is this and she said who is this i said this is his girlfriend she said he doesnt have a girlfriend i said give him the phone and he wont in about 5 minutes. anyways it ended where i just didnt know what to do because he told me it was his friend and he just didnt want to say anything because he didnt want me to start trouble. i said then why did you have to make it a big secret. im so confused. i love him too but i asked him if he loved me and he said he did a week ago for the first time but then when i asked him he said i dont love anything i have feelings for you tho. i said whatever. idk can anyone give me some advice? should i belive him? please help.