Should i test for prego? or am i worried?

my bf and i had may first. We used a condom and the contraceptive sponge. He also pulled out WAy before he came bec i finished him off a different way. about 2 days after i had little cramping and my stomach hurt alot some bloating my back hurt...i believe this was due to paranioa of being prego and it went away when i calmed down. so using this app on my ipod it has a calender to track your periods. i have used it before for about 2 cycles and i found out that i have a 29 day cycle. In march i took plan b bec i freaked out one night that my bf touched me after he touched himself (you know about pre ***) last month (april) it made my period 5 days late. i experienced cramping all the way up until my period came. This month (may) my ipod app said that my period was due the 17th. Its the 19th and I have to say im getting worried. My are starting to hurt and i was irritable but i honestly think its pms. I also broke out which usually happens after my period. I dont have cravings. Im not queesy. Today i started to cramp on and off (some where bad and some were dull). so should i be worried or does it look like my period is late bec of stress....please good answers and dont answer this question if your prego only if this has happend to you (kinda) or you actually think you can help me