advice? medication and pregnancy!!

One doctor proscriped me 'anti sickness tablets' well last few days I've been in agony with sharp pains in my stomach, just under my chest through into my back and my sides, also throwing up a lot. My partner rang my GP this morning and the doctor asked what tablets the hospital gave me which was "ondansetron" he said to tell me to stop taking them as there for cancer patients to stop bowl movement and I shouldn't be taking them but I've already taken the whole box😭 im between 7-8 weeks! Will I be ok or do I need to go hospital?