brainchild

Hello, last month I took the pill(combined) for 2 reasons, for my skin (spots) and for added contraceptive protection, (as well as condoms which we always use.) This meant that my cycle was shorter than normal, because normally it is about 5 weeks. I started taking it at the beginning of this month but stopped because not only were they making me feel a bit sicky, but I was running out of them and I was going on holiday and I didnt have time to go the docs and get some more!
just after I came back from my hols, about 3 weeks ago I have some slight bleeding for a few days, which is unusual, but I dont know if hat could be because I stopped and started taking the pill.
Now I should be due for my period around anytime now but it seems like aes nd ages since i had my last period, i think it was about 6 weeks ago. I have sore breasts like i always do just before my period but they have been sore for about 2-2 1/2 weeks now, at least, where usually they are sore for about 10 days only. I'm just wondering how likely it could be that I could be pregnant? Is there anything else that could cause the sore breasts for such a long time and the abnormal bleeding? I'm not sure if or how stress or anything affects it, but I did go abroad on holiday at the beginning of the month and also when i came home i found out that i had failed a uni module and I have loads of extra work to do. I usually come on around the end of the month but it seems like ages since i had a period, even my b/f has commented on it. i'm just worried about it.
Does anyone have any ideas? :-s Thankyou!