Could I be pregnant?

So I went off the pill waiting for my period to come on Monday, it's now Friday and still not here. The past 3 days I've been really nauseated and dry retching, random cramping and really emotional. My sense of smell has increased majorly and down below there's a huge increase in CM kinda like ovulation but worse. I am pretty strict with my pill but what's the chances..? It's happened before and I miscarried, could it happen again?! I'm scared if I am I'll lose it again :( we really want to have a baby just we wanna get our finances sorted first. Please help..