We had sex the 26th and 28th of November.  1st, 3rd, 5th, and 7th and 9th of December.  My discharge went from yellowish with kind of a smell to white and creamy. I've been waking up feeling sick and very thirsty. Some days a pounding head ache. I feel like I'm starving all day long. My back hurts and sometimes I have sharp pains in my boobs. I've also been cramping on my left side only. I've been gasy too. When I poop it's pebbly.. I know all pregnant a are different but my sister is currently 5 months pregnant and I told her what was going on and she said those were all first signs of pregnancy. My period is due the 18th. What do y'all think? Could I be?