Do you think he could have some 'colic'? Its meant to start around that time I think. Make sure you are properly burping him after each breast /bottle feed. It may seem obvious to some, but I never realised quite how difficult it was for my son to get the burps out - it took someone sitting there and pattying him / rubbing his back gently for ages to show me that he really did need to burp after each and every feed. At first I just thought after one or two attempts that he didn't need to, so would give it a rest, then wondered why he was so upset and unable to sleep for long. LOL. Its such a learning process.
For breast feeding - If the burping thing isn't it, try looking at your diet for potential allergens. Cutting back on the main culprits may help, but better to do it under someone's guidance - even your pediatrician may be able to offer some advice on that. Wheat and milk were the ones for us - especially milk. My son (3 yrs now) still can't tolerate much milk, so it was no wonder that he couldn't tolerate it even when it came through my system. Things did improve a bit when I cut them both out.
Milk is mainly a collection of white blood cells. So, its like they are drinking everything that's in your blood stream. And, everything that you eat or drink goes straight in there. If he's on the bottle, that could be another problem - could be having more trouble digesting it, or have an intolerance.
Good luck, rest as much as you can during the day when the baby rests. If you are relaxed and rested, the baby is more likely to be the same - take it from someone who resisted that for way too long and eventually paid the price. Its not worth trying to keep up with things and still do everything you used to do without sleep. Enjoy that baby, the amazing baby days go by far too quickly.
Hugs,
Ax