At the risk of being a know-it-all, (but also in recognition that this could be a revelation to someone out there)...
He could be hungry or overtired or teething. It sounds like a combination of the first two, if not all three. You have to eliminate one at a time, I would start with hunger. It's not popular on here, but consider the pros and cons of offering a bottle of formula to top him up. It's for you to decide, obviously, but if you've been exclusively bfing up until now and your milk supply is established then there aren't many downsides in supplementing with a bottle. A bottle is good at 5pm because it pretty much puts a stop to the constant feeding that would otherwise go on from 5-10pm (cluster feeding), a blessed relief to many mums who have other kids to look after or a million other things they'd rather be doing other than being on the couch feeding. So, bottle 5pm, bath, breastfeed 6.45pm, a good burp, then swaddle then bed. Old fashioned maternity nurse advice, but it has stood the test of time. The bottle is a 'test' really, in the sense that it can allow you to see if its hunger that's driving the rest of the behaviour you're seeing from your baby. If you rule hunger out you can go on to treat for teething.
Are you following a routine of any sort during the day? If not, now is a good time to think about the patterns you'd like to establish. Like, many people follow the pattern of feed immediately after baby wakes up, then change, then play for a bit, then nap. Again, not always popular on here, but the Baby Whisperer was very helpful for me and many of my friends in establishing routines. I found it created a very predictable day for me and very contented kids. Not everyone's a fan of the routine approach though, be warned. My babies thrived on it, so that's good enough for me.
Suggest you get Boots own teething gel once they are past 3 months. I've checked most of the gel in the shops, Boots own seems to have more of the active ingredients in. My Dd certainly seems to calm quicker & it lasts longer than bonjela or Dentinox. She started showing the same signs as yours around the same time, 2 teeth appeared at 5 months, hope you don't have to wait as long. 7 teeth by 10 months & another 4 are coming...
What a relief to know that if it IS teething he won't be like this for overly long. Have for Calpol in for his injections (just in case of fever) but will get bonjela into the medicine cabinet this week.
It's breaking my heart to see him in some of the states he gets himself into at the moment & has recently started to cry tears which made me cry the first time I saw it!
My DD cut both her bottom teeth at 13 weeks so teething had definitely begun by 8-9 weeks. I had a really bad couple of weeks with her till they came through, then things got better again so I'm sure he'll be okay soon :-)
The teeth are probably starting to move around under the gums ready to start making an appearance. Get some bonjela its brilliant and probably better than giving a 9 week old calpol. My DS had 2 teeth by 8 weeks. My mum pointed them out to me...I thought he was just being grumpy 0.O my DD started teething around 8-9 weeks but her teeth didn't appear til about 12-13 weeks. Both my kids teethed quite early, every baby is different my friends daughter didn't start until 8 months. Also with early teething you quite often have a bad week or two and then everything is back to normal for a couple of weeks so don't dispair that it'll be like this the whole time.
My DS was 9 weeks on Friday & since the Monday has had me in tears - mainly over his sudden aversion to taking daytime naps & subsequent draining behaviour: crying shortly after being put down & fighting me if I pick him up to soothe him. If he does fall asleep it's not for long & then he wakes crying.
At first I thought he was maybe just overtired, but I'm not so sure now as he doesn't seem much better if by some miracle he gets a decent nap. Also thought he was hungry, which is the case sometimes (after all he does need to feed in between all his unhappiness!) but he is only happy for a short while before it all starts again.
Aside from not napping, & crying on off ALL day I've noticed that he's drooling a lot more & often with bubbles on his lips; keeps shoving his hand in his mouth; if I pick him up coz he's crying & won't go to sleep he'll fight & rub his head from side to side on me making frantic sucking noises (hence why hunger was on my radar).
Is this normal?? Just when I think I'm getting the hang of this motherhood thing, something happens that makes me feel I know nothing about my son!!