I had a period 3 weeks ago , the next week i tried to conceive then last week i spotted for 2 days and eventually got a full period is this normal?

Could be normal...: Intercourse 7 days after onset of period is 2-3 days shy of the fertile window (5 to 6 days prior to release of egg). If spotting occurred around day 14 (day of ovulation) followed by a full period, you could rule out implantation bleeding with pregnancy test and consider having a pelvic exam if irregularities continue. But this could be normal irregularity caused by stress or other factors.