So sorry about your missed ab.
( I wouldn't assume the worst just yet. How far a long were you when you missed? I think the general rule of thumb is to have a good bit of time to allow the uterus to contract back into it's non-pregnant state (and for hormones to return to normal) before becoming pregnant again. There may be additional risks involved in being preggo so soon, but it might be fine. I wish you the best!