they told me that it will be hard to have another baby if I still have milk

Who in Hades told you that???? There are women that breastfeed that are pregnant with another child. So lets just dispell that myth right now!! From time to time (before I got pregnant again) my breasts leaked very little and it usually happened around the time my period was due. I guess you can chalk it up to hormone peak lol. If it worries you, go see you doctor for "dry up pills". But you can still get pregnant if your leaking.

My mom had milk until she hit menopause, and she got pregnant after a tubal.

I am currently breastfeeding a 15 month old AND pregnant. If you are menstruating more than likely you are ovulating. If you are concerned use ovulation prediction kits (you can use urine ones, or saliva, or you can chart basal body temperature. Also there is a blood test the doctor can do).

Also read this:
Do I need to wean to get pregnant?
http://www.kellymom.com/bf/normal/fertility.html#transition

get a breast pump