Newborn spits up from nose

I had my baby at 34 weeks hes currently 3 weeks old I breast feed him but mostly give him breast milk in bottle because he falls asleep fast at my breast and doesn't get enough milk but my point is he always spits up and its comes out his nose and mouth once he almost choked and I had to use the suctioner to take out the excess milk now I use it all the time because milk always comes out his nose is this normal should I be worried

P.s I went to the hospital they did him an ultrasound on his tummy no obstruction and they did exrays on his lungs and no milk is there so they dont know I'm just worried first child btw..