how soon is too soon?

We lost our baby on March 17 and had to have a D&C. We waited the two weeks my doctor suggested before having sex I started on birth control the week after the D&C but we didn't use a back up method of birth control. Per the birth control I'm suppose to start my period on Sunday but I've had some weird cramping like a pinching pulling feeling. We were told to wait three periods before trying again I want to be pregnant but I'm terrified if I am the same thing will happen are we ready have we grieved our loss, and if I'm not Pregnant I'm going to feel crushed