Just got a positive

I have been ttc for 3 years with one Mmc start of this year. I'm due to start my ivf on 2nd dec so waiting for me period to start and it hasn't come I did a test this morning and it came back positive. I'm confused and frightened something bad is going to happen again. Does everyone get cramping in early pregnancy this is exactly what it felt like the last time and I had lost it :(