Can't fit maternity pants ..?

I am 4'8 and pre-pregnancy I weighed 80 pounds and wore a 00short. I am almost 15 weeks and have gained 8 pounds & my belly has already grown a lot. I can't seem to fit maternity pants in the thigh, leg, length and even waist. Even as my pregnancy progresses I won't fit them, I'm already grown out of my pants/shorts & I walk around with them unbuttoned. What are some alternatives especially to get me through summer..?