Scared to write this down in case it is true but I think I could be pregnant. No idea about my cycle, not sure when last period was but some time before 23rd November. Unprotected sex once on 16th December (with hindsight may have been ovulating as v horny). No period yet but tiny dark bleed today but no period. Worried now as seems it could have been implantation bleeding? When can I test and get an accurate result? I'm scared, a long way away from home and my partner for 4 weeks and this would be terrible timing.