What do I do. Wait or tell him now.

PLEASE HELP!!
I got the bar/ implanon put in a week ago. And I have been feeling queezy since and before hand but it's gotten worse since the bar. So to shut my brain up that it could be pregnancy cause it happens every time that I eat ANYTHING (except crackers) I did a pregnancy test.
Now quickly on my relation ship we've been together just over a year live to gether plan on moving down south together have planned out life sort of. Wanna have a baby in roughly 1.5-2yrs. As my partner isn't ready.
So did pregnancy test well wat do u know positive. Go and get a clear blue pregnancy and walla pregnant 3+ weeks. Last period was in April on the 14th so not that far. I have since has a roller coaster night brothers girlfriend helping me out and mums friend to. I have had miscarriages with previous r partners and I am so worried it's going to happen again.
So firstly - I just needed to get it all off my chest and written down
But secondly - how in the world do I tell my partner. I love him with every fibre in my body but I no he's just not ready. Should I wait till I'm past 12 weeks to tell him and know that this baby is staying where it is. Or do I just tell him now. And hope to god everything goes ok.
Also the bar is out and done.
Sorry for long message anything will be helpful as long as it's possible I am slightly pooping myself.