Is this a positive???????

Clare
I had my daughter 4 months ago and EBF. I haven't had my period yet and thoughts I'd do a pregnancy test for fun this morning. It didn't look positive after about 20 seconds so I threw it in the bin. I took it out this evening when throwing something else away and now it has a vertical positive line! The control line is a bit faded on one side so is it really a positive? Or a false positive after having a baby? It's only a cheap supermarket brand test. 
Now I'm so worried!!! Please tell me what you think!