Stomach flu vs pregnancy symptoms

I got stomach flu last weekend, went to urgent care and tested negative for pregnancy (5 dpo last sunday), this morning seems like my stomach flu coming back again, watery stool (diarrhea) and nausea, drank 2 caplets of Imodium and 1 Zofran. I’m in 11 dpo today, could I be pregnant? I haven’t use pregnancy test yet since it’s not 5 days sooner than my expected period (5/6/18 -28th days cycle). Should I check it now by using Clearblue advanced pregnancy test? I’m afraid I got negative result since it’s not time to check yet, or I’ll get my hopes up for nothing. Are Imodium and Zofran intake are safe for TTC and pregnant women? Please help, thank you