Has my boyfriend cheated?

my boyfriend was going out last saturday night and when i sat next tohim before he went out it looked like he had a condom in his pocket and when he had left i went upstairs and looked in his drawer because there was one always there and it was gawn i just felt so sick i confronted him and he thought i was on about something else but it asnt till the next day he knew what i was really on about he acted calm and said i should have trusted him and shouldnt have went thru his drawers bt i thought i saw it he came down that night but we hardly spoke them monday night came and he came down we ended up having a big arguement he said iam ****** up in the head and parranoid but i trusted him 110% and now i dno what to do i feel sick and have hardly ate please help