Sicky baby!

So my baby boy is 6 weeks old today and this has only occurred in the last week or so….

After his feeds we keep him upright for at least 15-20 mins for his milk to go down and he always burps lovely… we lay him down for his sleep and he seems to sick up (what I would say) quite a lot of his milk?!

We have not changed his milk but you can hear it sitting on his chest almost like it hasn’t gone down…

I’m a FTM so I have nothing to compare this to and he doesn’t seem to be in any pain whatsoever but it’s enough milk/sick to drench his whole arm and chest of his sleep-suit so we are constantly changing him… which isn’t a problem at all I’m just worried about him bringing it back up!

Any ideas or advice??? Thank you!