You could possible be pregnant, especially if you have missed a few pills. However, your belly would not start growing until you were probably 5 months pregnant or more (unless there were multiples). If you have been having these sporatic bleeding episodes, then you should see a doctor ASAP. You could be having some very serious complications that would need immediate medical attention, especially if you are pregnant.
Of course you know I'm going to say you should see your Dr. Aside from that, yes, it is possible you're pregnant if you missed four pills. And while at 11 weeks the baby is barely big enough to be "showing", a lot of women get a kind of pregnancy bloat and nothing seems to fit. This happened to me with my pregnanies. I would hit six weeks and nothing in my closet fit. Another solution may be that you're spotting because of the pill. Some women get what is called break through bleeding and they will bleed at different times throughout their cycle. Either way, I'd see the Dr just to make sure everything is ok. Good luck!
You shouldn't be asking here, you should be asking your doctor. If you don't have a doctor, go to the emergency room. You need to find a doctor, if you don't have one, because he will keep track of your health and it will help in diagnosis.