Am i pregnant or just paranoid??

hi , my names lizzie. my situation is , me and one of my best friends ended up sleeping together about 2 months ago . We stupidly did not use a condom, but i have been on the pill for almost 2 years now ( and yes i know the pill does not protect you from STD's).. but at the time we slept together i had been taking my pill irregulary and missing daysnd not taking them at the right time .... i asked him if he had cum inside me or not and he told me that hes not sure but he dosent think he did ( but not sure isnt going to put my mind at rest.).. i didnt think anything of the situation until a about 2 weeks after when i started feeling sick for no reason, i couldnt sleep, i had constant headaches, i had pains and crampsin the lower part of my stomach .. but i knew my period was due in 2 weeks, so i waited... since going on the pill my period's are like clock work . but this time my period came 3 days late and all it was, was a bit of spotting anhen a slight heavier bleed towards the end . but not like they usually are... but i figured since i was bleeding that had to be a good sign because i know itsrare that women had normal periods when pregnant . so i started to forget the situation ... but 2 weeks on and i am stillving the same symptoms , plus breast pain, constant urination and it now hurts to sleep on my back because i get a pushing sensation on my bladder.... i came on my 2nd period this morning but its the same situation .. spotting and then a little heavier towards the end ... I am to scared to buy a pregnancy test or go to my doctors ... Am i pregnant or just paranoid?? please any advice would be great .... i need to try and put my mind at rest. thankyou.