Excellent news on here today
Heather & Jo - Congrats on the 2 embies. Good luck for ET
Kerry & Helen - Yipeeeee, congratulations! Really pleased for you both
Brown blood usually is fine as it's old blood, so probably is implantation bleeding. It's only if it's bright red with cramping you have need for concern - and even then I've read of people on the boards having this and continuing with a healthy pregnancy

Some cramping is also very normal in early pregnancy, I had AF type pains from the day after I got my BFP. The changes in your body happen rapidly, so don't panic if you feel AF pains - think of them more as pregnancy pains as your body stretches to accommodate your baby
Hope that helps reassure you a little - I know it's not easy to not worry. But, you will probably have to get used to that now, as the worrying never ends
Love
Jayne x