Hi Momo
Some babies are high-contact, high-input, some aren't. Congratulations, you got a high everything one! My DD was the same. But d'you know what? My high-contact child was/is incredibly self-sufficient, confident, sociable, entertaining (if challenging) and funny. And hugely rewarding. So all the doom-mongers who told me I'd have a clingy and fearful child if I carried her around and basically gave her what she needed, were proved wrong. Again.
I do hear your frustration, but at 14 wks you can't do much about your DSs instincts (cos it really ain't behaviour yet - at least not on a conscious level). You can, however, do something (temporarily) about your expectations of yourself and of him.
Second omaoma's sling and 'only plan 1 or 2 things into your day' recommendations. Both worked for me.
If your (or your DPs/family's) expectations of what you should be able to get done in a day are spoiling your first few months with your child, ditch the expectations.
Get out to the park/some baby groups/anything that you can enjoy and have adult conversation during at the same time as knowing you're providing stimulation for your DS.
Oh - and not wishing to be a profit of doom myself, the 4 month mark is a very fussy period for lots of babies. It's when the neo-cortex kicks in and there's loads of brain development going on, and it can really freak out some little ones as their world is almost literally changing before their eyes - it would make anyone clingy! It will settle down, honest.
Good luck!