The reading I've done says it takes up from 3-18 months for ovulation to start again. So if you are planning on having kids - I would switch methods.
i have only been on the depo for 3 months and havent gotten mine either iv researched the topic and i found out it can lower the chance of you ever getting pregnant or if you do get pregnant you can test negative on a hpt and have a miscarage do to the low hormones..... iv been off the depo for about 2 weeks now and i still havent gotten my period.... so i would say my personal oppinion would be yes switch to the pills.... good luck!!