how can i ok increase my situps in 1 month for pt test?

Doubling your situp count in a month is fine; three times or more may cause back pain, or other problems.

SEE YOUR DOCTOR before you start; your pregnancy may have left you vulnerable to hernias.

To make whatever progress you can, you will need to stand, sit, and move differently, so that your 'core' is training all the time.

A Pilates move called the 'Pelvic Curl' will help. Do it frequently so that it becomes a habit.

For about the first ten days, no situps. Instead, train your 'core' with other exercises such as 'Garhammer' knee-lifts or by kicking a punchbag, every other day, and with twisting moves every day.

For your second ten-day 'rotation', train less intensely so that you can train every day, alternating core exercise (as many different types as you can) days with situp days.

About ten days out, drop the other exercises so that you can concentrate on crunches and situps.

Try to leave two COMPLETE rest-days (light cardio is fine, but NO core-work) before your test.