i also have a baby around the same age (born sept. 09).....i know what you are going thru.....and i also have a 2.5 yr old and a 4 year old. i too have days when i hope my best is good enough.....i too wanted this more than anything....and i too say or think things that i regret when i'm frustrated and overwhelmed. nobody is perfect....it IS very hard to take care of kids....all you can do is try your best.
for my little guy, i try to divert his attention and keep him occupied...usually that keeps him more content. as we go about our day, i move him from bouncy seat, swing, bumbo seat, floor, high chair, and lots of time cuddling in my arms in between of course. i give him different toys, sit him in front of a mirror, etc. i put on music and dance around for him while i wash the dishes or cook or whatever. it seems that a constant change of scenery interests him. i also make sure that he is well rested, so he isnt nearly as fussy....he takes a short morning nap, a long mid-day nap, and a short early evening nap before going to bed around 8pm. i still nurse him about every 2-3 hours, but this week we started him on some rice cereal and that seemed to make him more content as well. as for the teething, he loves to chew on baby toys, and i put a little bit of orajel on his gums at night if he seems to be crying in pain.
coming from a mom that has done this 3 times in the last 4 years, i know that it DOES get easier........shortly she will be talking and telling you what she wants/needs, and playing with you, and you will be on a much more predictable schedule.
hang in there, and dont be too hard on yourself.....