I have had trouble with my very demanding DD si...

I have had trouble with my very demanding DD since day 1. I have posted several f my issueson huggies before. She is now 8 weeks old. I have beeb extremely exhausted with her constant want to nurse and screaming and resistig sleep at other times. The Dr has checked her out and says she is is healthy but she just cries a lot and doesnt sleep much. She is near impossible to settle. So on Thursday my body has really started reacting to the stress and exhaustion. I developed mastitis. On top of the sore breast, fever and flu like symtoms I got a massive coldsore and infected gum. Since having her I am 4kg below my pre pregnancy weight so have lost 18kg in 8 weeks and I was quite thin to start. I broke down tonight as I just feel my body can not take it anymore. DH was not supportive initially of me giving up bf before 6monthe but afyer seeing how moserable and stressed I am he wants me to start enjoying being a mum and said I could syart weaning or at least mix feeding whenever I like. The problem now is everyone was so against formula earlier that I feel guilty. At the same time I long for some freedom and just to enjoy myself again. Breastfeeding has made me so misreable and rundown that I am not sure how long I can keep it up. I dont know if I am looking for answers here but has anyone been on the same boat?