No Sit ups for 6 months???

So I wil be 6 weeks post TT on Thursday.  I saw my PS yesterday and everything is great.  She said i could start working out again, but no sit ups for 6 months.   I tried to do one on Saturday and i couldn't even get off the floor.  My core is so week.  what can I do to strengthen it?

Any stabilization exercise that ttightens your abs without stressing them. Ease into doing breathing ab. contractions while setting or standing. Exhale and contract your abs, just do a few and increase when your soreness is light.

Pilates and/or yoga work

can you do the plank?  it is supposed to be one of the best core exercises.