needing advice 😞

So , at 13weeks I experienced  heavy bleeding and cramping . Took myself to the hospital because I was so afraid of it being a miscarriage. Before then I have been spotting with light cramps for about 2 weeks .  They told me the baby was fine ,super strong heartbeat checked blood and urine and they couldn't find anything wrong.  I then followed up with my OB and he told me it could possibly be a blood clot behind the placenta. And that it would subside in a few weeks .  Never scheduled an ultrasound or anything.  Im now  16 weeks pregnant and I'm pregnant with my second child and with my daughter I never had any trouble and I know they say your 2nd is usually the hardest 😔 . But I'm still having the same problem ,I have an appointment on the 9th of this month and I'm hoping he spends a little more time on trying to figure out what this can possibly be . Maybe I should try looking for a new OB ? Not too sure what to do I just know it's extremely uncomfortable not knowing what's going on whether or not I should be on bed rest ?!! He literally spent 6 minutes with me 😔 if anyone has any advice it'd sure help me out a lot , thank you !!