Should i wait to tell him that I am pregnant? I am not sure if he will believe that it is his. 😩

Please don't judge me I know that I am not perfect. I been with my boyfriend for quite some time he's in the military and I just finished my college semester. We have sex every so often but, nothing more hit me than finding out that I am about to be a mother I know how stupid that sounds. I just took a test about 5 different brands (I know I am in shock) and came out positive. We use the pull out method as we did it careful but, still that never worked. We are about to go to a camping trip next weekend and there will be drinks and if I don't drink than he would suspect something... I don't want to tell him because he's going to his home town in the 21st for two weeks and I don't want him to worry about it or simple be stressed out. He won't believe that it is his because he doesn't believe he has precum or some sorts we been using this method for many months.I am just soo stressed out...