possible pregnancy? on birth control??

Emma
warning long post!!!
do you think I could be pregnant or is this just my birth control side effects?
I started taking lo loestrin fe on August 5th. 
these are the days I've had unprotected sex.  I've spotted on the 15th and today the 31st I started getting a little bit of brownish reddish blood but I took last nights pill 5 hours late. over the last few weeks I've put on a lot of weight, especially in my belly and thighs,  been really emotional and quick to cry, I've been nonstop craving Mexican food and im always hungry but I used to not have any appetite,
 im peeing a lot more, I've been getting headaches, and today I almost vomited 3 times but I held it back. 
does this sound like birth control or pregnancy? if I need to when should I test? 
sorry im just a bit worried and stressed about everything.. please give me advice?? 
thanks!!