Low HCG level at 18 DPO after IUI

Hi guys! So I got my first faint positive after my 2nd medicated IUI (clomid and ovidrel). I got my first beta on Tuesday which would have been 16 DPIUI and that level was Only 7. That night I started bleeding bright red blood blood exactly like a period. I was told to come in 48 hrs later to make sure it returned to zero since it looked like it would be a chemical. Today’s beta was 18 at 18 DPO. My question is: should I even keep hope alive? I really don’t have any hope but my husband is so hopefully. I was fully ready to go back to zero today and try again this month. Now with it up to 18 at 18 DPO, that still seems SO, SO LOW! I’m going back Saturday to see what my level is then. Has anyone had this happen before? Their level was low but lingered increasing only very very slightly but then dropping off? Thanks so much guys, I can’t stop crying!