I've only had a quick scan of thread responses but I feel your pain Motherbeyond. There is a chance it is reflux as others have said. However my colicky boy threw up from time to time due to me feeding on top of the wind, as he fed so much for comfort due to the pain, he was on me a lot. It took me a while to realise that though. But do go and see the GP just in case.
It took with my second baby who was very windy up to 10 weeks to settle easier. Even at feeds at night he'd squirm with wind after and be uncomfortable for ages. Co-sleep if it helps for now, if you don't already?
My second child cried for 2 to 3 hours a night until aged 10 weeks and I got so desperate (and hadn't really discovered mumsnet yet) that I spoke to my health visitor about it, she was really helpful and agreed it was probably colic and her tips to try were:
Warm bath covering tummy.
Lying him on his tummy with a warm (not hot) hot water bottle under him to soothe tummy.
Cycling his legs whilst he's on his back. Holding feet palm to palm and rocking legs sideways, whilst lying on floor or lap.
Or scooping with right hand down his right side whilst holding feet palm to palm.
Or rocking him face down well supported on legs.
She also said don't eat anything that gives you wind such as brocolli, cabbage, caffeine, cauliflower, garlic or other stimulants. She said if none of the above did work I could try buying Colief drops from a chemist and mixing in with feed by expressing it first, as she said sometimes colic is caused by a lactose intolerance.
I found that out of all of those the cycling the legs was particularly good. I don't think changing my diet helped at all tbh thinking back. I also found that as he had trouble burping, the infacol made him cry harder as it coalesced the bubbles into one big one that still went downwards but hurt more. But giving him gripe water after every feed straight away really soothed his tummy. I had to do it every feed though without fail.
The warm bath in quiet room was also a real help. Every night at the time he started to get agitated I would put in the bath, in a bath cradle and keep putting warm water on his tummy and every now and then top the bath up with warm water, so it wouldn't get too cold for him. Once or twice he was in the bath for 2 hours in the early days as it was really calming for him. Once he started doing big yawns and it was bedtime, I'd take him out into a dark bedroom and change him and BF him quietly and then often he'd go to sleep straight away. His poor sister ended up watching a lot of television in those early days. It was hard going.
Things will get better soon lovely, you must be shattered with 2 DCs already, sending you a hug x