good that you needed not to have axillary dissection for lymph nodes. not much except for a few lymph nodes and little fat (little only!) was lost. probably, the strange feeling is due to the wound. it's normal! remember to go to check up regularly. if i were you, i would keep going to the specialist doctor for follow up. breast cancer is an indolent disease. 5 year surveillance is not enough.
have enough (but not too much) rest and have a happy heart. it is really not easy to take care of 2 young babies now.
probably not just fat. it is quite "standard" procedure now to check if there is lymph node involvement. your good news is that there is no lymph node involvement.