Bleeding again 13 weeks😥 UPDATE

On my way to the hospital again. Woke up and was bleeding it wasn't pouring out just when i wiped. Rang the maternity unit and said i should come in to get checked and have a blood test (as im o neg they need to double check before giving me the injection i need, i forget what its called). Its only when i wipe not much, im wearing a pad but its been 2 hours and there's only scanty bits on it. I had this before at 8 weeks and it stopped after a day or so but cause was inknown. I'm Cramping a little bit I'm also severely constipated atm (sorry tmi)they did say it could be that because straining can cause bleeding. I only had a scan last week he was jumping around like a 2 year old eating haribos😁. Has anyone had this and there baby been ok ?

UPDATE

So i went to hospital had a blood test had to wait 2 hours to confirm I'm o neg, and had an anti d injection. They gave me a quick scan and his heart was beating away fast asleep after all the troble he's caused ! Theres nothing they can see thats causing the bleeding. I've Got go have a cervix check at gp when bleeding stopped as dont have a clue whats happening. But babys fine. Thankyou to everyone that replyed x