Clocked out 15 minutes for the past 2 days?

Hello,im a courtesy clerk at a local grocerie store.Except,Im having a problem clocking into the system! I show up to work on time and I clock in exactly on time all the time except.Monday,was my first day of work and showed up on time and got to work.Well near the end of my shift this person got mad at the cashier because of a coupon or something and I was the one who had to take everything back!! Try taking 33 food products back to there location when you dont know where any of the food is and your new to the job! Well I was late 15 minutes that day! And Tuesday I was so close to clocking out on time! On my way up the stairs the cashier called me right at the last minute and asked me to help take this guy's cart and food out! The guy took like 5 minutes to open his car doors and took 4 minutes to get everything in the car! And he was also using a mart cart so I had to take it back to the store and plug it up! I was also 15 minutes late on Tuesday! I dont know what to do! I really like my job and need this job,but there going to think im frauding the clock! I love helping the customers and I have much respect for my job,but I cant keep clocking out late.Any advice? Im really worried about tomorrow! Thanks!