it has to be all in my head....right?

Normally i'm a very logical person..so it doesn't make much sense for me to be wondering if i'm pregnant. I have the copper iud and it has one of the highest success rates out there. plus i am pretty much on my period right now..only it's early and my body is acting rather strange. It's not terribly early, just like 4 or 5 days..Normally i have it for about a whole week (yeah it sucks), this time it's not lasting quite as long but there is still plenty of blood. much more than they say implantation bleeding is. So pretty much the only reason i'm wondering is because my husband and i had a romantic weekend filled with lots of intimate time together..then i got my period early, about 5 days after the fun filled weekend..the strange part is that in the last week i've been exhausted like i have only been 1 other time in my life (prego), i could easily sleep till 11 and am ready to drop by 9..plus i've been getting headaches and have been nauseous. yesterday i actually had to leave the house because the smell of dinner and the cleanup after ward was making me so sick.. smells have only ever really effected me like that when i was pregnant. So i'm thinking this all has to be in my head.. But is there anyone out there who has had something like a full period in early pregnancy? I'm thinking i'm just paranoid because i hear about the chances of getting pregnant and losing the baby with the iud and really don't want something like that to happen.