The endometrial thickness varies in relation to the stage of the menstrual cycle and you have not mentioned on which day you got the sonogram done and if you have regular cycles. Thin endometrium
post-ovulation can cause implantation
difficulties but can be treated with proper and timely hormonal
supplementation. You should be evaluated further for other difficulties and a complete hormonal profile taken and the results compiled to plan a treatment strategy. It is always possible to get pregnant if thin endometrium is corrected. Please have further advice from your gynecologist. Good luck.