Implantation bleeding?!

Looking for advice really..I am 4 weeks pregnant today (4 weeks since the first day of my last period) I had a few stomach cramps yesterday (very light) and have just been to the toilet and my discharge is ever so slightly brown (very very light) is this normal/ ok? I had a miscarriage back in February at 9 weeks and that started with dark brown blood (which this isn’t!) but obviously am a bit worried! Any advice/ reassurance would be great! Thank you!