Last time, it took me 9 months to lose the baby weight. I had gained about 45 pounds, and I lost it all. This time, I'm planning to gain less, but I'm a slow loser, so still expect it to take me months to lose whatever I gain.
Even after losing it all, not all clothes fit the same! Some things were tight, while others were too big. It was really strange.
Your baby is only 8 weeks old. Your uterus might still be stretched, too. Please, don't be too hard on yourself. It's wonderful that you're so motivated to lose the weight, but you don't have to do it all at once.
I wore maternity pants for 2 months. I purchased a few pairs of inexpensive, regular pants/jeans to get me through as I lost my weight.