Weed and pregnancy laws in uk? Anyone help?

I quit for the first few weeks of my pregnancy after smoking every single day for 8 years to help with an old eating disorder, anxiety issues, and sleep..... however now the morning sickness has kicked in like a bitch... and weed is the only thing that helps me, I try and use edibles most of the time to avoid smoke.... anyone know the laws in uk if they test and stuff? Thanks