Still at prepregnancy weight 34 weeks

Question for my plus sized mommas. During my first trimester, I lost about 15lbs from my prepregnancy weight. Currently I am 34 weeks and have been back to my prepregnancy weight for about 4 weeks now. Went to my appointment today and actually had lost a couple pounds from my appointment two weeks ago. OB didn't seem too worried so I assume this isn't anything to worry about either. My baby belly is pretty big so it honestly astounds me that I weigh the same right now that I did before getting pregnant.

What I am wondering is has anyone experienced similar, and directly after giving birth, how much of that weight was baby/fluid/placenta weight?

Also, I want to clarify that I am not doing anything to keep weight off. I am eating pretty much the same as I always have and I am not exercising.