breastfeeding...

This may be TMI for some people, specifically if you are of the male persuasion. Kevin and I will be married three years in June, I have spent almost that entire three years either pregnant or breastfeeding. I started struggling last month to get Sofie to nurse, she just wasn't very interested. I thought I was feeling pretty burnt out on nursing anyways and thought maybe it was time for formula, I was not sure how much effort I wanted to put into keeping her nursing. So two days ago I bought our first can of formula (we had a few samples we have used a couple times before but this was the first can we had bought)... I was excited to make the switch, to have my body to myself again...so I thought...
I nursed Sofie for what I thought would be the last time that night... and began to CRY!!! Suddenly I realized I wasnt ready to make the switch... I was attatched to nursing... I was going to encourage her as much as I could to nurse for atleast a few more months. Folks I really didnt think I had this much attatchment so I was totaly blindsided by the tears. I think it was a realization that she was growing up, when I stopped nursing Averi I was pregnant with Sofie so I didn't go through these same emotions...this time Im not pregnant and a part of me wants to keep Sof my baby!
THEN we went to her check up today. Sofie had gained 2 oz since her 4 month check up, the doctor was not too happy. I told him I stuggle to get her to nurse more then a couple of minutes four times a day (this is before she eats solids) and thatwhen I pump it is only 4-5 oz. He explained she needed atleast 16-24 oz a day and was probably only getting a mere 12-15 from me. He encouraged me to keep trying but said if she didnt nurse atleast 4-5 times a day for a minimum of 10 minutes it may be time to switch her to formula. At this point I am still going to try, he suggested nursing her in a calm quiet room (like that is easy to do when Im home by myself with a wild two year old all day)... I am accepting formula may be the best option if she doesnt start to nurse better and focusing on the positives of formula while also focusing on fulfilling nursing sessions for us both.