Low hcg levels

Has anyone started off with low hcg level around 5 weeks and went by to get them checked after two days they they jumped up a lot? I know it’s kinda a silly question but I’m stressing myself out.. my hcg was 266 yesterday and I’m supposed to be 5 weeks and 3 days, I go back tomorrow for a retest and I’m just so worried they aren’t progressing correctly.. I’ve also had brown spotting since last Wednesday.